hw-breakpoints: Include only linux/perf_event.h from kernel part of bp headers

As userspace only needs the breakpoints enum types from the
breakpoints headers.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Prasad <prasad@linux.vnet.ibm.com>
LKML-Reference: <1258987355-8751-1-git-send-email-fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

include/linux/hw_breakpoint.h

 #ifndef _LINUX_HW_BREAKPOINT_H
 #define _LINUX_HW_BREAKPOINT_H
 
-#include <linux/perf_event.h>
-
 enum {
 	HW_BREAKPOINT_LEN_1 = 1,
 	HW_BREAKPOINT_LEN_2 = 2,
@@ -19,6 +17,8 @@ enum {
 #ifdef __KERNEL__
 #ifdef CONFIG_HAVE_HW_BREAKPOINT
 
+#include <linux/perf_event.h>
+
 static inline unsigned long hw_breakpoint_addr(struct perf_event *bp)
 {
 	return bp->attr.bp_addr;