meson: Require TPM2 for measuring utilities

I happened to run build with openssl but no tpm2 and ran into issues
like:

        [313/1382] Compiling C object systemd-measure.p/src_boot_measure.c.o
        FAILED: systemd-measure.p/src_boot_measure.c.o
        cc -Isystemd-measure.p -I. -I.. -Isrc/basic -I../src/basic -Isrc/fundamental -I../src/fundamental -Isrc/systemd -I../src/systemd -I../src/libsystemd/sd-bus -I../src/libsystemd/sd-device -I../src/libsystemd/sd-event -I../src/libsystemd/sd-hwdb -I../src/libsystemd/sd-id128 -I../src/libsystemd/sd-journal -I../src/libsystemd/sd-netlink -I../src/libsystemd/sd-network -I../src/libsystemd/sd-resolve -Isrc/shared -I../src/shared -fdiagnostics-color=always -D_FILE_OFFSET_BITS=64 -Wall -Winvalid-pch -Wextra -std=gnu11 -O0 -g -Wno-missing-field-initializers -Wno-unused-parameter -Wdate-time -Wendif-labels -Werror=format=2 -Werror=format-signedness -Werror=implicit-function-declaration -Werror=incompatible-pointer-types -Werror=int-conversion -Werror=overflow -Werror=override-init -Werror=return-type -Werror=shift-count-overflow -Werror=shift-overflow=2 -Werror=undef -Wfloat-equal -Wimplicit-fallthrough=5 -Winit-self -Wlogical-op -Wmissing-include-dirs -Wmissing-noreturn -Wnested-externs -Wold-style-definition -Wpointer-arith -Wredundant-decls -Wshadow -Wstrict-aliasing=2 -Wstrict-prototypes -Wsuggest-attribute=noreturn -Wunused-function -Wwrite-strings -Wno-unused-result -Werror=missing-declarations -Werror=missing-prototypes -fdiagnostics-show-option -fno-common -fno-strict-aliasing -fstack-protector -fstack-protector-strong -fvisibility=hidden --param=ssp-buffer-size=4 -fno-omit-frame-pointer -Werror=shadow -include config.h -DOPENSSL_LOAD_CONF -MD -MQ systemd-measure.p/src_boot_measure.c.o -MF systemd-measure.p/src_boot_measure.c.o.d -o systemd-measure.p/src_boot_measure.c.o -c ../src/boot/measure.c
        ../src/boot/measure.c: In function ‘verb_sign’:
        ../src/boot/measure.c:710:48: error: variable ‘c’ has initializer but incomplete type
          710 |         _cleanup_(tpm2_context_destroy) struct tpm2_context c = {};

        [308/1382] Compiling C object systemd-pcrphase.p/src_boot_pcrphase.c.o
        FAILED: systemd-pcrphase.p/src_boot_pcrphase.c.o
        cc -Isystemd-pcrphase.p -I. -I.. -Isrc/basic -I../src/basic -Isrc/fundamental -I../src/fundamental -Isrc/systemd -I../src/systemd -I../src/libsystemd/sd-bus -I../src/libsystemd/sd-device -I../src/libsystemd/sd-event -I../src/libsystemd/sd-hwdb -I../src/libsystemd/sd-id128 -I../src/libsystemd/sd-journal -I../src/libsystemd/sd-netlink -I../src/libsystemd/sd-network -I../src/libsystemd/sd-resolve -Isrc/shared -I../src/shared -fdiagnostics-color=always -D_FILE_OFFSET_BITS=64 -Wall -Winvalid-pch -Wextra -std=gnu11 -O0 -g -Wno-missing-field-initializers -Wno-unused-parameter -Wdate-time -Wendif-labels -Werror=format=2 -Werror=format-signedness -Werror=implicit-function-declaration -Werror=incompatible-pointer-types -Werror=int-conversion -Werror=overflow -Werror=override-init -Werror=return-type -Werror=shift-count-overflow -Werror=shift-overflow=2 -Werror=undef -Wfloat-equal -Wimplicit-fallthrough=5 -Winit-self -Wlogical-op -Wmissing-include-dirs -Wmissing-noreturn -Wnested-externs -Wold-style-definition -Wpointer-arith -Wredundant-decls -Wshadow -Wstrict-aliasing=2 -Wstrict-prototypes -Wsuggest-attribute=noreturn -Wunused-function -Wwrite-strings -Wno-unused-result -Werror=missing-declarations -Werror=missing-prototypes -fdiagnostics-show-option -fno-common -fno-strict-aliasing -fstack-protector -fstack-protector-strong -fvisibility=hidden --param=ssp-buffer-size=4 -fno-omit-frame-pointer -Werror=shadow -include config.h -DOPENSSL_LOAD_CONF -MD -MQ systemd-pcrphase.p/src_boot_pcrphase.c.o -MF systemd-pcrphase.p/src_boot_pcrphase.c.o.d -o systemd-pcrphase.p/src_boot_pcrphase.c.o -c ../src/boot/pcrphase.c
        ../src/boot/pcrphase.c: In function ‘determine_banks’:
        ../src/boot/pcrphase.c:117:24: error: unknown type name ‘TPMI_ALG_HASH’
          117 |         _cleanup_free_ TPMI_ALG_HASH *algs = NULL;

Guarding the utilites with HAVE_TPM2 fixes the issue for me.

This complements #24811.

meson.build

@@ -2573,7 +2573,7 @@ if conf.get('HAVE_BLKID') == 1 and conf.get('HAVE_GNU_EFI') == 1
                 install : true,
                 install_dir : systemgeneratordir)
 
-        if conf.get('HAVE_OPENSSL') == 1
+        if conf.get('HAVE_OPENSSL') == 1 and conf.get('HAVE_TPM2') == 1
                 executable(
                         'systemd-measure',
                         'src/boot/measure.c',