perf bpf: No need to include headers just use forward declarations

In the bpf-prologue.h header we are just using pointers, so no need to
include headers for that, just provide forward declarations for those
types.

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

tools/perf/util/bpf-prologue.h

···
 #ifndef __BPF_PROLOGUE_H
 #define __BPF_PROLOGUE_H
 
-#include <linux/compiler.h>
-#include <linux/filter.h>
-#include "probe-event.h"
+struct probe_trace_arg;
+struct bpf_insn;
 
 #define BPF_PROLOGUE_MAX_ARGS 3
 #define BPF_PROLOGUE_START_ARG_REG BPF_REG_3
···
 		      struct bpf_insn *new_prog, size_t *new_cnt,
 		      size_t cnt_space);
 #else
+#include <linux/compiler.h>
 #include <errno.h>
 
 static inline int