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/SBx81LIFKW_defconfig b/configs/SBx81LIFKW_defconfig
index 238a1c4..19a1a23 100644
--- a/configs/SBx81LIFKW_defconfig
+++ b/configs/SBx81LIFKW_defconfig
@@ -11,6 +11,7 @@
 CONFIG_DEFAULT_DEVICE_TREE="kirkwood-atl-sbx81lifkw"
 CONFIG_IDENT_STRING="\nSBx81LIFKW"
 # CONFIG_SYS_MALLOC_F is not set
+CONFIG_SYS_LOAD_ADDR=0x1000000
 CONFIG_BOOTDELAY=3
 CONFIG_SILENT_CONSOLE=y
 CONFIG_SILENT_U_BOOT_ONLY=y