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/colibri_vf_defconfig b/configs/colibri_vf_defconfig
index abb8117..2b9151d 100644
--- a/configs/colibri_vf_defconfig
+++ b/configs/colibri_vf_defconfig
@@ -12,6 +12,7 @@
 CONFIG_DEFAULT_DEVICE_TREE="vf610-colibri"
 CONFIG_TARGET_COLIBRI_VF=y
 CONFIG_ENV_VARS_UBOOT_CONFIG=y
+CONFIG_SYS_LOAD_ADDR=0x80008000
 CONFIG_SYS_EXTRA_OPTIONS="IMX_CONFIG=board/toradex/colibri_vf/imximage.cfg,IMX_NAND"
 CONFIG_BOOTDELAY=1
 CONFIG_USE_PREBOOT=y