io_uring: remove extra ->file check

It won't ever get into io_prep_rw() when req->file haven't been set in
io_req_set_file(), hence remove the check.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

fs/io_uring.c

@@ -1862,9 +1862,6 @@ static int io_prep_rw(struct io_kiocb *req, const struct io_uring_sqe *sqe,
 	unsigned ioprio;
 	int ret;
 
-	if (!req->file)
-		return -EBADF;
-
 	if (S_ISREG(file_inode(req->file)->i_mode))
 		req->flags |= REQ_F_ISREG;