perf/x86: Remove unused variable in nhmex_rbox_alter_er()

The variable port is initialized but never used
otherwise, so remove the unused variable.

dpatch engine is used to auto generate this patch.
(https://github.com/weiyj/dpatch)

Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
Cc: Yan, Zheng <zheng.z.yan@intel.com>
Cc: a.p.zijlstra@chello.nl
Cc: paulus@samba.org
Cc: acme@ghostprotocols.net
Link: http://lkml.kernel.org/r/CAPgLHd8NZkYSkZm22FpZxiEh6HcA0q-V%3D29vdnheiDhgrJZ%2Byw@mail.gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>