drm/omap: Fix error handling path in 'omap_dmm_probe()'

If we don't find a matching device node, we must free the memory allocated
in 'omap_dmm' a few lines above.

Fixes: 7cb0d6c1 ("drm/omap: fix TILER on OMAP5")
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>

drivers/gpu/drm/omapdrm/omap_dmm_tiler.c

@@ -638,7 +638,8 @@ static int omap_dmm_probe(struct platform_device *dev)
 		match = of_match_node(dmm_of_match, dev->dev.of_node);
 		if (!match) {
 			dev_err(&dev->dev, "failed to find matching device node\n");
-			return -ENODEV;
+			ret = -ENODEV;
+			goto fail;
 		}
 
 		omap_dmm->plat_data = match->data;