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/clearfog_gt_8k_defconfig b/configs/clearfog_gt_8k_defconfig
index c94d63e..89b978d 100644
--- a/configs/clearfog_gt_8k_defconfig
+++ b/configs/clearfog_gt_8k_defconfig
@@ -16,6 +16,7 @@
 CONFIG_AHCI=y
 CONFIG_DISTRO_DEFAULTS=y
 # CONFIG_SYS_MALLOC_CLEAR_ON_INIT is not set
+CONFIG_SYS_LOAD_ADDR=0x800000
 CONFIG_USE_PREBOOT=y
 CONFIG_SYS_CONSOLE_INFO_QUIET=y
 # CONFIG_DISPLAY_CPUINFO is not set