CIFS: Fix duplicate line introduced by clone_file_range patch

Commit 04b38d60 ("vfs: pull btrfs clone API to vfs layer")
added a duplicated line (in cifsfs.c) which causes a sparse compile
warning.
Signed-off-by: Steve French <steve.french@primarydata.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>

fs/cifs/cifsfs.c

@@ -1013,7 +1013,6 @@ const struct file_operations cifs_file_strict_ops = {
 	.llseek = cifs_llseek,
 	.unlocked_ioctl	= cifs_ioctl,
 	.clone_file_range = cifs_clone_file_range,
-	.clone_file_range = cifs_clone_file_range,
 	.setlease = cifs_setlease,
 	.fallocate = cifs_fallocate,
 };