bpf, docs: Add loongarch64 as arch supporting BPF JIT

As BPF JIT support for loongarch64 was added about one year ago
with commit 5dc615520c4d ("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 <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Martin KaFai Lau <[e-mail]>

Documentation/admin-guide/sysctl/net.rst

···
   - s390x
   - riscv64
   - riscv32
+  - loongarch64
 
 And the older cBPF JIT supported on the following archs:
 

Documentation/networking/filter.rst

···
 
 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
 -------