Convert CONFIG_ENABLE_36BIT_PHYS to Kconfig

This converts the following to Kconfig:
   CONFIG_ENABLE_36BIT_PHYS

Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/arch/powerpc/cpu/mpc85xx/Kconfig b/arch/powerpc/cpu/mpc85xx/Kconfig
index 02efa1c..5510bc7 100644
--- a/arch/powerpc/cpu/mpc85xx/Kconfig
+++ b/arch/powerpc/cpu/mpc85xx/Kconfig
@@ -1185,6 +1185,9 @@
 		Defines divider of platform clock(clock input to
 		eLBC controller).
 
+config ENABLE_36BIT_PHYS
+	bool "Enable 36bit physical address space support"
+
 config SYS_MPC85XX_NO_RESETVEC
 	bool "Discard resetvec section and move bootpg section up"
 	depends on MPC85xx