perf tools: Add missing linux/compiler.h include to perf-sys.h

It uses the likely/unlikely macros, so need to include
<linux/compiler.h>.

Cc: Adrian Hunter <[e-mail]>
Cc: David Ahern <[e-mail]>
Cc: Jiri Olsa <[e-mail]>
Cc: Namhyung Kim <[e-mail]>
Cc: Wang Nan <[e-mail]>
Link: http://lkml.kernel.org/n/[e-mail]
Signed-off-by: Arnaldo Carvalho de Melo <[e-mail]>

tools/perf/perf-sys.h

···
 #include <sys/types.h>
 #include <sys/syscall.h>
 #include <linux/types.h>
+#include <linux/compiler.h>
 #include <linux/perf_event.h>
 #include <asm/barrier.h>