mmc: pci: Fix Kconfig dependency

The PCI MMC driver depends on the generic MMC SDHCI driver,
otherwise it does not compile.

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Jaehoon Chung <jh80.chung@samsung.com>
diff --git a/drivers/mmc/Kconfig b/drivers/mmc/Kconfig
index f8ca52e..c34fce3 100644
--- a/drivers/mmc/Kconfig
+++ b/drivers/mmc/Kconfig
@@ -311,6 +311,7 @@
 
 config MMC_PCI
 	bool "Support for MMC controllers on PCI"
+	depends on MMC_SDHCI
 	help
 	  This selects PCI-based MMC controllers.
 	  If you have an MMC controller on a PCI bus, say Y here.