f2fs: remove device type check for direct IO

To ensure serialized IOs, f2fs allows only LFS mode for zoned
device. Remove redundant check for direct IO.

Signed-off-by: Eunhee Rho <eunhee83.rho@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

fs/f2fs/f2fs.h

@@ -4502,12 +4502,7 @@ static inline bool f2fs_force_buffered_io(struct inode *inode,
 	/* disallow direct IO if any of devices has unaligned blksize */
 	if (f2fs_is_multi_device(sbi) && !sbi->aligned_blksize)
 		return true;
-	/*
-	 * for blkzoned device, fallback direct IO to buffered IO, so
-	 * all IOs can be serialized by log-structured write.
-	 */
-	if (f2fs_sb_has_blkzoned(sbi))
-		return true;
+
 	if (f2fs_lfs_mode(sbi) && (rw == WRITE)) {
 		if (block_unaligned_IO(inode, iocb, iter))
 			return true;