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/kp_imx53_defconfig b/configs/kp_imx53_defconfig
index abca864..dd3d2d7 100644
--- a/configs/kp_imx53_defconfig
+++ b/configs/kp_imx53_defconfig
@@ -8,6 +8,7 @@
 CONFIG_DEFAULT_DEVICE_TREE="imx53-kp"
 CONFIG_ENV_OFFSET_REDUND=0x102000
 # CONFIG_CMD_BMODE is not set
+CONFIG_SYS_LOAD_ADDR=0x72000000
 CONFIG_FIT=y
 CONFIG_SUPPORT_RAW_INITRD=y
 CONFIG_SYS_EXTRA_OPTIONS="IMX_CONFIG=board/freescale/mx53loco/imximage.cfg"