riscv: bpf: Move bpf_jit_alloc_exec() and bpf_jit_free_exec() to core

[ Upstream commit 1d27d854 ]

We will drop the executable permissions of the code pages from the
mapping at allocation time soon. Move bpf_jit_alloc_exec() and
bpf_jit_free_exec() to bpf_jit_core.c so that they can be shared by
both RV64I and RV32I.

Signed-off-by: Jisheng Zhang <jszhang@kernel.org>
Acked-by: Luke Nelson <luke.r.nels@gmail.com>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
Stable-dep-of: c56fb2aa ("riscv, bpf: Fix inconsistent JIT image generation")
Signed-off-by: Sasha Levin <sashal@kernel.org>