mmc: sdhci-s3c: fix missing clock for gpio card-detect

2abeb5c5ded2 ("Add clk_(enable/disable) in runtime suspend/resume")
added the capability to stop the clocks when the device is runtime
suspended, but forgot to handle the case of the card-detect using
an external gpio.

Therefore in the case that runtime-pm is enabled, start the io-clock
when a card is inserted and stop it again once it is removed.

Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Signed-off-by: Chris Ball <cjb@laptop.org>

drivers/mmc/host/sdhci-s3c.c

@@ -373,18 +373,25 @@ static struct sdhci_ops sdhci_s3c_ops = {
 static void sdhci_s3c_notify_change(struct platform_device *dev, int state)
 {
 	struct sdhci_host *host = platform_get_drvdata(dev);
+	struct sdhci_s3c *sc = sdhci_priv(host);
 	unsigned long flags;
 
 	if (host) {
 		spin_lock_irqsave(&host->lock, flags);
 		if (state) {
 			dev_dbg(&dev->dev, "card inserted.\n");
+#ifdef CONFIG_PM_RUNTIME
+			clk_prepare_enable(sc->clk_io);
+#endif
 			host->flags &= ~SDHCI_DEVICE_DEAD;
 			host->quirks |= SDHCI_QUIRK_BROKEN_CARD_DETECTION;
 		} else {
 			dev_dbg(&dev->dev, "card removed.\n");
 			host->flags |= SDHCI_DEVICE_DEAD;
 			host->quirks &= ~SDHCI_QUIRK_BROKEN_CARD_DETECTION;
+#ifdef CONFIG_PM_RUNTIME
+			clk_disable_unprepare(sc->clk_io);
+#endif
 		}
 		tasklet_schedule(&host->card_tasklet);
 		spin_unlock_irqrestore(&host->lock, flags);