ring-buffer: Remove abandoned macro RB_MISSED_FLAGS

This macro isn't used since commit d325c402 ("ring-buffer: Remove
unused function ring_buffer_page_len()"), so better to remove it.

Link: http://lkml.kernel.org/r/1579586080-45300-1-git-send-email-alex.shi@linux.alibaba.comSigned-off-by: Alex Shi <alex.shi@linux.alibaba.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

kernel/trace/ring_buffer.c

@@ -300,8 +300,6 @@ u64 ring_buffer_event_time_stamp(struct ring_buffer_event *event)
 /* Missed count stored at end */
 #define RB_MISSED_STORED	(1 << 30)
 
-#define RB_MISSED_FLAGS		(RB_MISSED_EVENTS|RB_MISSED_STORED)
-
 struct buffer_data_page {
 	u64		 time_stamp;	/* page time stamp */
 	local_t		 commit;	/* write committed index */