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/configs/T2080RDB_NAND_defconfig b/configs/T2080RDB_NAND_defconfig
index c33ff6f..2b5249c 100644
--- a/configs/T2080RDB_NAND_defconfig
+++ b/configs/T2080RDB_NAND_defconfig
@@ -15,6 +15,7 @@
 CONFIG_SPL=y
 CONFIG_MPC85xx=y
 CONFIG_TARGET_T2080RDB=y
+CONFIG_ENABLE_36BIT_PHYS=y
 CONFIG_SYS_MPC85XX_NO_RESETVEC=y
 CONFIG_SPL_SYS_MPC85XX_NO_RESETVEC=y
 CONFIG_SYS_MEMTEST_START=0x00200000