arm64: extend execmem_info for generated code allocations

The memory allocations for kprobes and BPF on arm64 can be placed
anywhere in vmalloc address space and currently this is implemented with
overrides of alloc_insn_page() and bpf_jit_alloc_exec() in arm64.

Define EXECMEM_KPROBES and EXECMEM_BPF ranges in arm64::execmem_info and
drop overrides of alloc_insn_page() and bpf_jit_alloc_exec().

Signed-off-by: Mike Rapoport (IBM) <rppt@kernel.org>
Acked-by: Will Deacon <will@kernel.org>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>