hw-breakpoints: Add two reserved fields for future extensions

Add two reserved fields for future extensions in the hardware
breakpoints interface. Further needs may arise.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: "K. Prasad" <prasad@linux.vnet.ibm.com>

include/linux/perf_event.h

@@ -220,6 +220,8 @@ struct perf_event_attr {
 			__u64		bp_addr;
 			__u32		bp_type;
 			__u32		bp_len;
+			__u64		__bp_reserved_1;
+			__u64		__bp_reserved_2;
 		};
 	};