drm/mediatek/mtk_mipi_tx: checking the wrong variable

We should be checking "phy_provider" here not "phy".

Fixes: 2e54c14e ('drm/mediatek: Add DSI sub driver')
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Matthias Brugger <matthias.bgg@gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/20160701135934.GA15723@mwanda

drivers/gpu/drm/mediatek/mtk_mipi_tx.c

@@ -431,7 +431,7 @@ static int mtk_mipi_tx_probe(struct platform_device *pdev)
 	phy_set_drvdata(phy, mipi_tx);
 
 	phy_provider = devm_of_phy_provider_register(dev, of_phy_simple_xlate);
-	if (IS_ERR(phy)) {
+	if (IS_ERR(phy_provider)) {
 		ret = PTR_ERR(phy_provider);
 		return ret;
 	}