perf: Fix broken union in 'struct perf_event_mmap_page'

The capabilities bits must not be "union'ed" together.
Put them in a separate struct.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1372425741-1676-2-git-send-email-adrian.hunter@intel.comSigned-off-by: Ingo Molnar <mingo@kernel.org>

include/uapi/linux/perf_event.h

@@ -375,10 +375,12 @@ struct perf_event_mmap_page {
 	__u64	time_running;		/* time event on cpu */
 	union {
 		__u64	capabilities;
+		struct {
 			__u64	cap_usr_time		: 1,
 				cap_usr_rdpmc		: 1,
 				cap_____res		: 62;
 		};
+	};
 
 	/*
 	 * If cap_usr_rdpmc this field provides the bit-width of the value