f2fs: fix the msg data type

Data type of msg in f2fs_write_checkpoint trace should
be const char * instead of char *.
Signed-off-by: Mukesh Ojha <quic_mojha@quicinc.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

include/trace/events/f2fs.h

@@ -1404,7 +1404,7 @@ TRACE_EVENT(f2fs_readpages,
 
 TRACE_EVENT(f2fs_write_checkpoint,
 
-	TP_PROTO(struct super_block *sb, int reason, char *msg),
+	TP_PROTO(struct super_block *sb, int reason, const char *msg),
 
 	TP_ARGS(sb, reason, msg),