gfs2: Silence gcc format-truncation warning

Enlarge sd_fsname to be big enough for the longest long lock table name
and an arbitrary journal number.  This silences two -Wformat-truncation
warnings with gcc 7.1.1.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
diff --git a/fs/gfs2/incore.h b/fs/gfs2/incore.h
index 0ce0b33..6e18e97 100644
--- a/fs/gfs2/incore.h
+++ b/fs/gfs2/incore.h
@@ -833,7 +833,7 @@ struct gfs2_sbd {
 	atomic_t sd_freeze_state;
 	struct mutex sd_freeze_mutex;
 
-	char sd_fsname[GFS2_FSNAME_LEN];
+	char sd_fsname[GFS2_FSNAME_LEN + 3 * sizeof(int) + 2];
 	char sd_table_name[GFS2_FSNAME_LEN];
 	char sd_proto_name[GFS2_FSNAME_LEN];