arm64: bpf: add 'shift by register' instructions

arm64: bpf: add 'shift by register' instructions

Commit 31e7e4742fba ("bpf: x86: add missing 'shift by register'
instructions to x64 eBPF JIT") noted support for 'shift by register'
in eBPF and added support for it for x64. Let's enable this for arm64
as well.

The arm64 eBPF JIT compiler now passes the new 'shift by register'
test case introduced in the same commit 31e7e4742fba.

Signed-off-by: Zi Shen Lim <zlim.lnx@gmail.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Alexei Starovoitov <ast@plumgrid.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>