mmc: mxs-mmc: disable regulator on error and in the remove function

The 'reg_vmmc' regulator is enabled in the probe. It is never disabled.
Neither in the error handling path of the probe nor in the remove
function.

Register a devm_action to disable it when needed.

Fixes: 4dc5a79f1350 ("mmc: mxs-mmc: enable regulator for mmc slot")
Signed-off-by: Christophe JAILLET <[e-mail]>
Link: https://lore.kernel.org/r/4aadb3c978[e-mail]
Signed-off-by: Ulf Hansson <[e-mail]>

drivers/mmc/host/mxs-mmc.c

···
 };
 MODULE_DEVICE_TABLE(of, mxs_mmc_dt_ids);
 
+static void mxs_mmc_regulator_disable(void *regulator)
+{
+	regulator_disable(regulator);
+}
+
 static int mxs_mmc_probe(struct platform_device *pdev)
 {
 	struct device_node *np = pdev->dev.of_node;
···
 				"Failed to enable vmmc regulator: %d\n", ret);
 			goto out_mmc_free;
 		}
+
+		ret = devm_add_action_or_reset(&pdev->dev, mxs_mmc_regulator_disable,
+					       reg_vmmc);
+		if (ret)
+			goto out_mmc_free;
 	}
 
 	ssp->clk = devm_clk_get(&pdev->dev, NULL);