arc: Migrate ARC_MMU_VER to Kconfig

Move this value to Kconfig.

Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/arch/arc/Kconfig b/arch/arc/Kconfig
index 1a7c525..6ae66bb 100644
--- a/arch/arc/Kconfig
+++ b/arch/arc/Kconfig
@@ -102,6 +102,13 @@
 
 endchoice
 
+config ARC_MMU_VER
+	int
+	default 0 if ARC_MMU_ABSENT
+	default 2 if ARC_MMU_V2
+	default 3 if ARC_MMU_V3
+	default 4 if ARC_MMU_V4
+
 config CPU_BIG_ENDIAN
 	bool "Enable Big Endian Mode"
 	help