perf tools: Add union u64_swap type for swapping u64 data

The following union:
union {
u64 val64;
u32 val32[2];
} u;

is used on more than one place in perf code and will be used more in
upcomming patches.

Adding union u64_swap to have it defined globaly so we dont need to
redefine it all the time.

Signed-off-by: Jiri Olsa <[e-mail]>
Reviewed-by: David Ahern <[e-mail]>
Tested-by: David Ahern <[e-mail]>
Cc: Corey Ashford <[e-mail]>
Cc: David Ahern <[e-mail]>
Cc: Frederic Weisbecker <[e-mail]>
Cc: Ingo Molnar <[e-mail]>
Cc: Paul Mackerras <[e-mail]>
Cc: Peter Zijlstra <[e-mail]>
Link: http://lkml.kernel.org/r/[e-mail]
Signed-off-by: Arnaldo Carvalho de Melo <[e-mail]>

tools/perf/util/evsel.c

···
 	 * used for cross-endian analysis. See git commit 65014ab3
 	 * for why this goofiness is needed.
 	 */
-	union {
-		u64 val64;
-		u32 val32[2];
-	} u;
+	union u64_swap u;
 
 	memset(data, 0, sizeof(*data));
 	data->cpu = data->pid = data->tid = -1;
···
 	 * used for cross-endian analysis. See git commit 65014ab3
 	 * for why this goofiness is needed.
 	 */
-	union {
-		u64 val64;
-		u32 val32[2];
-	} u;
+	union u64_swap u;
 
 	array = event->sample.array;
 

tools/perf/util/types.h

···
 typedef unsigned char	   u8;
 typedef signed char	   s8;
 
+union u64_swap {
+	u64 val64;
+	u32 val32[2];
+};
+
 #endif /* __PERF_TYPES_H */