mmc: tangier: Add Intel Tangier eMMC/SDHCI driver

This patch adds Intel Tangier eMMC/SDHCI driver.

Intel Tangier SoC contains a hybrid of PCI and non-PCI devices. SDHCI
controller is one of the devices which are *not* on a PCI and, hence,
cannot be enumerated by standard PCI means. This driver, allows for
SDHCI controller on Tangier SoC to work in U-Boot.

Signed-off-by: Vincent Tinelli <vincent.tinelli@intel.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
diff --git a/drivers/mmc/Kconfig b/drivers/mmc/Kconfig
index 78091cc..05e0b10 100644
--- a/drivers/mmc/Kconfig
+++ b/drivers/mmc/Kconfig
@@ -325,6 +325,20 @@
 
 	  If unsure, say N.
 
+config MMC_SDHCI_TANGIER
+	bool "Tangier SDHCI controller support"
+	depends on DM_MMC && BLK
+	depends on MMC_SDHCI
+	help
+	  This selects support for SDHCI controller on Tanginer
+	  SoC. Note that this controller does not sit on PCI bus and,
+	  hence, cannot be enumerated by standard PCI means.
+
+	  If you're using an Intel Tangier SoC (available on Intel
+	  Edison board), say Y here.
+
+	  If unsure, say N.
+
 config MMC_SDHCI_TEGRA
 	bool "SDHCI platform support for the Tegra SD/MMC Controller"
 	depends on TEGRA