kconfig: mmc: move pxa_mmc_generic to kconfig

Move CONFIG_PXA_MMC_GENERIC to Kconfig.

Signed-off-by: Marcel Ziswiler <marcel@ziswiler.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/drivers/mmc/Kconfig b/drivers/mmc/Kconfig
index 33b128d..ad86c23 100644
--- a/drivers/mmc/Kconfig
+++ b/drivers/mmc/Kconfig
@@ -299,6 +299,14 @@
 
 	  If unsure, say N.
 
+config PXA_MMC_GENERIC
+	bool "Support for MMC controllers on PXA"
+	help
+	  This selects MMC controllers on PXA.
+	  If you are on a PXA architecture, say Y here.
+
+	  If unsure, say N.
+
 config MMC_OMAP_HS
 	bool "TI OMAP High Speed Multimedia Card Interface support"
 	select DM_REGULATOR_PBIAS if DM_MMC && DM_REGULATOR