Convert CONFIG_SYS_LOAD_ADDR to Kconfig

Now that we have consistent usage, migrate this symbol to Kconfig.

Signed-off-by: Tom Rini <trini@konsulko.com>
Reviewed-by: Rick Chen <rick@andestech.com>
diff --git a/configs/mx53loco_defconfig b/configs/mx53loco_defconfig
index 07c6ca4..49e103d 100644
--- a/configs/mx53loco_defconfig
+++ b/configs/mx53loco_defconfig
@@ -12,6 +12,7 @@
 CONFIG_DM_GPIO=y
 CONFIG_DEFAULT_DEVICE_TREE="imx53-qsb"
 # CONFIG_CMD_BMODE is not set
+CONFIG_SYS_LOAD_ADDR=0x72000000
 CONFIG_SUPPORT_RAW_INITRD=y
 CONFIG_SYS_EXTRA_OPTIONS="IMX_CONFIG=board/freescale/mx53loco/imximage.cfg"
 CONFIG_USE_PREBOOT=y