perf unwind arm64: Remove needless event.h & thread.h includes

To reduce compile time and header dependency chains just add forward
declarations for pointer types and include linux/types.h for u64.

Signed-off-by: Arnaldo Carvalho de Melo <[e-mail]>

tools/perf/util/arm64-frame-pointer-unwind-support.h

···
 #ifndef __PERF_ARM_FRAME_POINTER_UNWIND_SUPPORT_H
 #define __PERF_ARM_FRAME_POINTER_UNWIND_SUPPORT_H
 
-#include "event.h"
-#include "thread.h"
+#include <linux/types.h>
+
+struct perf_sample;
+struct thread;
 
 u64 get_leaf_frame_caller_aarch64(struct perf_sample *sample, struct thread *thread, int user_idx);