mmc: Fix use of wrong device in mmc_gpiod_free_cd()

mmc_gpiod_free_cd() is paired with mmc_gpiod_request_cd()
and both must reference the same device which is the
actual host controller device not the mmc_host class
device.
Signed-off-by: NAdrian Hunter <adrian.hunter@intel.com>
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>

drivers/mmc/core/slot-gpio.c

@@ -390,7 +390,7 @@ void mmc_gpiod_free_cd(struct mmc_host *host)
 		host->slot.cd_irq = -EINVAL;
 	}
 
-	devm_gpiod_put(&host->class_dev, ctx->cd_gpio);
+	devm_gpiod_put(host->parent, ctx->cd_gpio);
 
 	ctx->cd_gpio = NULL;
 }