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/origen_defconfig b/configs/origen_defconfig
index 932c107..883446e 100644
--- a/configs/origen_defconfig
+++ b/configs/origen_defconfig
@@ -12,6 +12,7 @@
 CONFIG_SPL=y
 CONFIG_IDENT_STRING=" for ORIGEN"
 CONFIG_DISTRO_DEFAULTS=y
+CONFIG_SYS_LOAD_ADDR=0x43e00000
 # CONFIG_USE_BOOTCOMMAND is not set
 CONFIG_SYS_CONSOLE_IS_IN_ENV=y
 CONFIG_SYS_CONSOLE_INFO_QUIET=y