drm/omap: dmm_tiler: fix return error code in omap_dmm_probe()

Return -ENOMEM when allocating refill memory failed.

Fixes: 71e8831f ("drm/omap: DMM/TILER support for OMAP4+ platform")
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20201117061045.3452287-1-yangyingliang@huawei.com

drivers/gpu/drm/omapdrm/omap_dmm_tiler.c

@@ -889,6 +889,7 @@ static int omap_dmm_probe(struct platform_device *dev)
 					   &omap_dmm->refill_pa, GFP_KERNEL);
 	if (!omap_dmm->refill_va) {
 		dev_err(&dev->dev, "could not allocate refill memory\n");
+		ret = -ENOMEM;
 		goto fail;
 	}