Fix:

 arch/x86/kernel/cpu/perf_event.h:377:43: sparse: dubious one-bit signed bitfield

Cc: Borislav Petkov <bp@amd64.org>
Reported-by: NFengguang Wu <fengguang.wu@intel.com>
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/n/tip-2jxkmktkppkclj1qe6qxd7ah@git.kernel.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>