[bpf] change llvm-objdump to print dec instead of hex

since bpf instruction stream is multiple of 8 change llvm-objdump
to print decimal instruction number instead of hex address, so that
users don't have to do this math manually to match kernel verifier output

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
llvm-svn: 289569