soc: imx: gpcv2: print errno for regulator errors

Make debugging of power management issues easier by printing the reason
why a regulator fails to be enabled or disabled.
Signed-off-by: Martin Kepplinger <martin.kepplinger@puri.sm>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

drivers/soc/imx/gpcv2.c

@@ -328,7 +328,9 @@ static int imx_pgc_power_up(struct generic_pm_domain *genpd)
 	if (!IS_ERR(domain->regulator)) {
 		ret = regulator_enable(domain->regulator);
 		if (ret) {
-			dev_err(domain->dev, "failed to enable regulator\n");
+			dev_err(domain->dev,
+				"failed to enable regulator: %pe\n",
+				ERR_PTR(ret));
 			goto out_put_pm;
 		}
 	}
@@ -467,7 +469,9 @@ static int imx_pgc_power_down(struct generic_pm_domain *genpd)
 	if (!IS_ERR(domain->regulator)) {
 		ret = regulator_disable(domain->regulator);
 		if (ret) {
-			dev_err(domain->dev, "failed to disable regulator\n");
+			dev_err(domain->dev,
+				"failed to disable regulator: %pe\n",
+				ERR_PTR(ret));
 			return ret;
 		}
 	}