perf/x86: Fix P6 driver section warning

Fix a compile warning - 'a section type conflict' by removing
__initconst.

Signed-off-by: yangyongqiang <yangyongqiang01@baidu.com>
Cc: Cyrill Gorcunov <gorcunov@gmail.com>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>