x86: Convert MMC to driver model

Convert the pci_mmc driver over to driver model and migrate all x86 boards
that use it.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Tested-by: Bin Meng <bmeng.cn@gmail.com>
diff --git a/arch/Kconfig b/arch/Kconfig
index 826e346..2528f50 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -85,6 +85,7 @@
 	select DM_SPI
 	select DM_SPI_FLASH
 	select USB_EHCI_HCD
+	select DM_MMC if MMC
 
 config XTENSA
 	bool "Xtensa architecture"