dma: Add a Kconfig for legacy DMA

We cannot use the existing DMA config for the MCD driver because it is
not migrated to driver model. In order to move it to drivers/Makefile
we need some sort of option for it. Add a new DMA_LEGACY option, which
also acts as a signal that it should be migrated.

Enable this for devkit3250 which uses CONFIG_DMA_LPC32XX which is not
converted to Kconfig.

For now this is not used in the Makefile. That update happens in a
following patch.
Signed-off-by: NSimon Glass <sjg@chromium.org>

drivers/dma/Kconfig

@@ -37,6 +37,7 @@ config BCM6348_IUDMA
 
 config TI_EDMA3
 	bool "TI EDMA3 driver"
+	select DMA_LEGACY
 	help
 	  Enable the TI EDMA3 driver for DRA7xx and AM43xx evms.
 	  This driver support data transfer between memory
@@ -57,6 +58,15 @@ config APBH_DMA_BURST8
 
 endif
 
+config DMA_LEGACY
+	bool "Legacy DMA support"
+	default y if FSLDMAFEC
+	help
+	  Enable legacy DMA support. This does not use driver model and should
+	  be migrated to the new API.
+
+	  It is required for some PowerPC boards.
+
 source "drivers/dma/ti/Kconfig"
 
 endmenu # menu "DMA Support"