mkosi: Drop _fixperms workaround

This was added to deal with a bug in the rpm 4.20 rc in Rawhide
but since that's been fixed, let's drop the workaround.

(cherry picked from commit 517e892210)

mkosi.images/build/mkosi.conf.d/centos-fedora/mkosi.build.chroot

@@ -100,7 +100,6 @@ CXX_LD="$( ((LLVM)) && echo lld)" \
     --define "__script_requires %{nil}" \
     --define "_find_debuginfo_opts --unique-debug-src-base \"%{name}\"" \
     --define "_find_debuginfo_dwz_opts %{nil}" \
-    --define "_fixperms true" \
     --undefine _package_note_flags \
     --noclean \
     "pkg/$PKG_SUBDIR/systemd.spec"

mkosi.images/build/mkosi.conf.d/opensuse/mkosi.build.chroot

@@ -97,7 +97,6 @@ build() {
         --define "__script_requires %{nil}" \
         --define "_find_debuginfo_dwz_opts %{nil}" \
         --define "_find_debuginfo_opts --unique-debug-src-base \"%{name}\"" \
-        --define "_fixperms true" \
         --noclean \
         "$@" \
         "pkg/$PKG_SUBDIR/systemd.spec"