f2fs: pass checkpoint reason on roll-forward recovery

This patch adds CP_RECOVERY to remain recovery information for checkpoint.
And, it makes sure writing checkpoint in this case.

Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

include/trace/events/f2fs.h

@@ -78,6 +78,7 @@
 		{ CP_UMOUNT,	"Umount" },				\
 		{ CP_FASTBOOT,	"Fastboot" },				\
 		{ CP_SYNC,	"Sync" },				\
+		{ CP_RECOVERY,	"Recovery" },				\
 		{ CP_DISCARD,	"Discard" })
 
 struct victim_sel_policy;