x86, CPU: Drop superfluous get_cpu_cap() prototype

The get_cpu_cap() external function prototype was declared twice
so lose one of them.

Clean up the header guard while at it.

Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>
Link: http://lkml.kernel.org/r/1322594083-14507-1-git-send-email-bp@amd64.org


Signed-off-by: Ingo Molnar <mingo@elte.hu>