perf tools: Move __used from perf.h to linux/compiler.h

Just like in the kernel and also to remove the need to include
perf.h in the symbol subsystem.

Signed-off-by: Arnaldo Carvalho de Melo <[e-mail]>
Cc: Frédéric Weisbecker <[e-mail]>
Cc: Mike Galbraith <[e-mail]>
Cc: Peter Zijlstra <[e-mail]>
Cc: Paul Mackerras <[e-mail]>
LKML-Reference: <[e-mail]>
Signed-off-by: Ingo Molnar <[e-mail]>

tools/perf/perf.h

···
 #define __user
 #define asmlinkage
 
-#define __used		__attribute__((__unused__))
-
 #define unlikely(x)	__builtin_expect(!!(x), 0)
 #define min(x, y) ({				\
 	typeof(x) _min1 = (x);			\

tools/perf/util/include/linux/compiler.h

···
 #define __user
 #define __attribute_const__
 
+#define __used		__attribute__((__unused__))
+
 #endif