drm/imx: imx-tve: check the value returned by regulator_set_voltage()

regulator_set_voltage() may fail, so we better check its return value
and propagate it in the case of error.

Signed-off-by: Fabio Estevam <fabio.estevam@nxp.com>
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
diff --git a/drivers/gpu/drm/imx/imx-tve.c b/drivers/gpu/drm/imx/imx-tve.c
index a293a7d..fe36309e 100644
--- a/drivers/gpu/drm/imx/imx-tve.c
+++ b/drivers/gpu/drm/imx/imx-tve.c
@@ -628,7 +628,9 @@
 
 	tve->dac_reg = devm_regulator_get(dev, "dac");
 	if (!IS_ERR(tve->dac_reg)) {
-		regulator_set_voltage(tve->dac_reg, 2750000, 2750000);
+		ret = regulator_set_voltage(tve->dac_reg, 2750000, 2750000);
+		if (ret)
+			return ret;
 		ret = regulator_enable(tve->dac_reg);
 		if (ret)
 			return ret;