ti: keystone: dma: Migrate to Kconfig

Move the main option for handling drivers/dma/keystone_nav* to Kconfig,
and enable it by default.  All of the sub-symbols are not configurable,
so remove them from the CONFIG namespace.

Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/drivers/dma/Kconfig b/drivers/dma/Kconfig
index bbeec79..9cacea8 100644
--- a/drivers/dma/Kconfig
+++ b/drivers/dma/Kconfig
@@ -53,6 +53,14 @@
 	  This driver support data transfer between memory
 	  regions.
 
+config TI_KSNAV
+	bool "TI Keystone Navigator DMA driver"
+	depends on ARCH_KEYSTONE
+	default y
+	select DMA_LEGACY
+	help
+	  Enable the Keystone Navigator driver for Keystone 2 platforms.
+
 config APBH_DMA
 	bool "Support APBH DMA"
 	depends on MX23 || MX28 || MX6 || MX7 || IMX8 || IMX8M