bpf, docs: Add loongarch64 as arch supporting BPF JIT

As BPF JIT support for loongarch64 was added about one year ago
with commit 5dc615520c ("LoongArch: Add BPF JIT support"), it
is appropriate to add loongarch64 as arch supporting BPF JIT in
bpf and sysctl docs as well.

Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Link: https://lore.kernel.org/r/1695111937-19697-1-git-send-email-yangtiezhu@loongson.cn
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>

Documentation/admin-guide/sysctl/net.rst

@@ -71,6 +71,7 @@ two flavors of JITs, the newer eBPF JIT currently supported on:
   - s390x
   - riscv64
   - riscv32
+  - loongarch64
 
 And the older cBPF JIT supported on the following archs:
 

Documentation/networking/filter.rst

@@ -650,8 +650,8 @@ before a conversion to the new layout is being done behind the scenes!
 
 Currently, the classic BPF format is being used for JITing on most
 32-bit architectures, whereas x86-64, aarch64, s390x, powerpc64,
-sparc64, arm32, riscv64, riscv32 perform JIT compilation from eBPF
-instruction set.
+sparc64, arm32, riscv64, riscv32, loongarch64 perform JIT compilation
+from eBPF instruction set.
 
 Testing
 -------