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/ci20_mmc_defconfig b/configs/ci20_mmc_defconfig
index c2efe39..2e515fb 100644
--- a/configs/ci20_mmc_defconfig
+++ b/configs/ci20_mmc_defconfig
@@ -11,6 +11,7 @@
 CONFIG_SPL_MMC_SUPPORT=y
 CONFIG_SPL=y
 CONFIG_ARCH_JZ47XX=y
+CONFIG_SYS_LOAD_ADDR=0x81000000
 CONFIG_FIT=y
 CONFIG_USE_BOOTARGS=y
 CONFIG_BOOTARGS="console=ttyS4,115200 rw rootwait root=/dev/mmcblk0p1"