perf tools: event.h needs asm/perf_regs.h

As it uses PERF_REGS_MAX, fix it.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/n/tip-2t232w0kcqu97xod8t2at2h0@git.kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/event.h

@@ -8,6 +8,7 @@
 #include "map.h"
 #include "build-id.h"
 #include "perf_regs.h"
+#include <asm/perf_regs.h>
 
 struct mmap_event {
 	struct perf_event_header header;