UBIFS: always print stacktrace when switching to R/O mode

When switching to R/O mode due to an I/O error, always dump the stack, not only
when debugging is enabled.
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>

fs/ubifs/io.c

@@ -86,7 +86,7 @@ void ubifs_ro_mode(struct ubifs_info *c, int err)
 		c->no_chk_data_crc = 0;
 		c->vfs_sb->s_flags |= MS_RDONLY;
 		ubifs_warn("switched to read-only mode, error %d", err);
-		dbg_dump_stack();
+		dump_stack();
 	}
 }