NFS: remove redundant code in nfs_file_write()

filemap_fdatawait_range() will always return 0, after patch 6c984083
("NFS: Use of mapping_set_error() results in spurious errors"), it will not
save the wb err in struct address_space->flags:

  result = filemap_fdatawait_range(file->f_mapping, ...) = 0
    filemap_check_errors(mapping) = 0
      test_bit(..., &mapping->flags) // flags is 0
Signed-off-by: ChenXiaoSong <chenxiaosong2@huawei.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

fs/nfs/file.c

@@ -663,8 +663,6 @@ ssize_t nfs_file_write(struct kiocb *iocb, struct iov_iter *from)
 		result = filemap_fdatawait_range(file->f_mapping,
 						 iocb->ki_pos - written,
 						 iocb->ki_pos - 1);
-		if (result < 0)
-			goto out;
 	}
 	result = generic_write_sync(iocb, written);
 	if (result < 0)