fs/direct-io.c: remove some left over checks

We know that "ret > 0" is true here.  These tests were left over from
commit 02afc27faec9 ('direct-io: Handle O_(D)SYNC AIO') and aren't
needed any more.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index 0165b86..7331a23 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -1797,7 +1797,7 @@
 	BTRFS_I(inode)->last_sub_trans = root->log_transid;
 	if (num_written > 0) {
 		err = generic_write_sync(file, pos, num_written);
-		if (err < 0 && num_written > 0)
+		if (err < 0)
 			num_written = err;
 	}