fsdax: remove a pointless __force cast in copy_cow_page_dax

Despite its name copy_user_page expected kernel addresses, which is what
we already have.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NDan Williams <dan.j.williams@intel.com>
Reviewed-by: NDarrick J. Wong <djwong@kernel.org>
Link: https://lore.kernel.org/r/20211129102203.2243509-13-hch@lst.deSigned-off-by: NDan Williams <dan.j.williams@intel.com>

fs/dax.c

@@ -728,7 +728,7 @@ static int copy_cow_page_dax(struct block_device *bdev, struct dax_device *dax_d
 		return rc;
 	}
 	vto = kmap_atomic(to);
-	copy_user_page(vto, (void __force *)kaddr, vaddr, to);
+	copy_user_page(vto, kaddr, vaddr, to);
 	kunmap_atomic(vto);
 	dax_read_unlock(id);
 	return 0;