sendfile: remove .sendfile from filesystems that use generic_file_sendfile()

They can use generic_file_splice_read() instead. Since sys_sendfile() now
prefers that, there should be no change in behaviour.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
diff --git a/fs/ufs/file.c b/fs/ufs/file.c
index 1e09632..6705d74 100644
--- a/fs/ufs/file.c
+++ b/fs/ufs/file.c
@@ -60,5 +60,5 @@
 	.mmap		= generic_file_mmap,
 	.open           = generic_file_open,
 	.fsync		= ufs_sync_file,
-	.sendfile	= generic_file_sendfile,
+	.splice_read	= generic_file_splice_read,
 };