mmc: sdhci: add card_event callback to sdhci

Add a card_event callback to sdhci so that clients can provide their
own card_event to be called when card_detect is triggered.

Signed-off-by: Christian Daudt <csd@broadcom.com>
Signed-off-by: Chris Ball <cjb@laptop.org>
diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
index 3ad3973..a78bd4f 100644
--- a/drivers/mmc/host/sdhci.c
+++ b/drivers/mmc/host/sdhci.c
@@ -2062,6 +2062,10 @@
 	struct sdhci_host *host = mmc_priv(mmc);
 	unsigned long flags;
 
+	/* First check if client has provided their own card event */
+	if (host->ops->card_event)
+		host->ops->card_event(host);
+
 	spin_lock_irqsave(&host->lock, flags);
 
 	/* Check host->mrq first in case we are runtime suspended */