f2fs: fix to consider multiple device for readonly check

This patch introduce f2fs_hw_is_readonly() to check whether lower
device is readonly or not, it adapts multiple device scenario.

Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

fs/f2fs/super.c

@@ -3377,7 +3377,7 @@ try_onemore:
 		 * mount should be failed, when device has readonly mode, and
 		 * previous checkpoint was not done by clean system shutdown.
 		 */
-		if (bdev_read_only(sb->s_bdev) &&
+		if (f2fs_hw_is_readonly(sbi) &&
 				!is_set_ckpt_flags(sbi, CP_UMOUNT_FLAG)) {
 			err = -EROFS;
 			goto free_meta;