drivers/mmc: Add realtek pcie sdmmc host driver

Realtek PCI-E SD/MMC card host driver is used to access SD/MMC card,
with the help of Realtek PCI-E card reader MFD driver.

Signed-off-by: Wei WANG <wei_wang@realsil.com.cn>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Tested-by: Borislav Petkov <bp@alien8.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/mmc/host/Kconfig b/drivers/mmc/host/Kconfig
index 9bf10e7..dfa6d56 100644
--- a/drivers/mmc/host/Kconfig
+++ b/drivers/mmc/host/Kconfig
@@ -621,3 +621,10 @@
 
 	  Note: These controllers only support SDIO cards and do not
 	  support MMC or SD memory cards.
+
+config MMC_REALTEK_PCI
+	tristate "Realtek PCI-E SD/MMC Card Interface Driver"
+	depends on MFD_RTSX_PCI
+	help
+	  Say Y here to include driver code to support SD/MMC card interface
+	  of Realtek PCI-E card reader