sdhci: Add sdhci_deferred_probe() API

Add the sdhci_deferred_probe() function to register as the
deferred_probe() callback to the mmc core. It will in turn call the
deferred_probe() callback of the platform drivers as declared in the
sdhci_ops.

Signed-off-by: Faiz Abbas <faiz_abbas@ti.com>
diff --git a/drivers/mmc/sdhci.c b/drivers/mmc/sdhci.c
index 9b7c5f8..520c9f9 100644
--- a/drivers/mmc/sdhci.c
+++ b/drivers/mmc/sdhci.c
@@ -658,6 +658,20 @@
 	return sdhci_init(mmc);
 }
 
+static int sdhci_deferred_probe(struct udevice *dev)
+{
+	int err;
+	struct mmc *mmc = mmc_get_mmc_dev(dev);
+	struct sdhci_host *host = mmc->priv;
+
+	if (host->ops && host->ops->deferred_probe) {
+		err = host->ops->deferred_probe(host);
+		if (err)
+			return err;
+	}
+	return 0;
+}
+
 static int sdhci_get_cd(struct udevice *dev)
 {
 	struct mmc *mmc = mmc_get_mmc_dev(dev);
@@ -692,6 +706,7 @@
 	.send_cmd	= sdhci_send_command,
 	.set_ios	= sdhci_set_ios,
 	.get_cd		= sdhci_get_cd,
+	.deferred_probe	= sdhci_deferred_probe,
 #ifdef MMC_SUPPORTS_TUNING
 	.execute_tuning	= sdhci_execute_tuning,
 #endif
diff --git a/include/sdhci.h b/include/sdhci.h
index 7f8feef..aa4378f 100644
--- a/include/sdhci.h
+++ b/include/sdhci.h
@@ -268,6 +268,7 @@
 	void	(*set_clock)(struct sdhci_host *host, u32 div);
 	int (*platform_execute_tuning)(struct mmc *host, u8 opcode);
 	void (*set_delay)(struct sdhci_host *host);
+	int	(*deferred_probe)(struct sdhci_host *host);
 };
 
 #if CONFIG_IS_ENABLED(MMC_SDHCI_ADMA)