bpf, x86: Remove unused cnt increase from EMIT macro

Removing unused cnt increase from EMIT macro together with cnt declarations.
This was introduced in commit [1] to ensure proper code generation. But that
code was removed in commit [2] and this extra code was left in.

  [1] b52f00e6 ("x86: bpf_jit: implement bpf_tail_call() helper")
  [2] ebf7d1f5 ("bpf, x64: rework pro/epilogue and tailcall handling in JIT")

Signed-off-by: Jiri Olsa <jolsa@redhat.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20210623112504.709856-1-jolsa@kernel.org