[PATCH net-next v3] arm: eBPF JIT compiler

With the below #ifdef __LITTLE_ENDIAN spanning the entire
bpf_int_jit_compile(), a user can then enable and compile
eBPF JIT for big endian, even set the bpf_jit_enable to 1
to turn it on, but it won't JIT anything, which is contrary
to the expectation.

This should rather be a hard dependency in the Kconfig, if
I got it correctly, expressed as e.g.

        select HAVE_EBPF_JIT if !CPU_ENDIAN_BE32

Will do it. That's a good catch. Thanks Daniel.