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_revD_SPIFLASH_defconfig b/configs/T2080RDB_revD_SPIFLASH_defconfig
index fbae2c4..9d629ad 100644
--- a/configs/T2080RDB_revD_SPIFLASH_defconfig
+++ b/configs/T2080RDB_revD_SPIFLASH_defconfig
@@ -18,6 +18,7 @@
 CONFIG_SPL_SPI=y
 CONFIG_MPC85xx=y
 CONFIG_TARGET_T2080RDB=y
+CONFIG_ENABLE_36BIT_PHYS=y
 CONFIG_SYS_MPC85XX_NO_RESETVEC=y
 CONFIG_T2080RDB_REV_D=y
 CONFIG_SYS_MEMTEST_START=0x00200000