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_pxa270_defconfig b/configs/colibri_pxa270_defconfig
index 814d87e..7223a4d 100644
--- a/configs/colibri_pxa270_defconfig
+++ b/configs/colibri_pxa270_defconfig
@@ -8,6 +8,7 @@
 CONFIG_ENV_SIZE=0x40000
 CONFIG_ENV_SECT_SIZE=0x40000
 CONFIG_ENV_VARS_UBOOT_CONFIG=y
+CONFIG_SYS_LOAD_ADDR=0xa0000000
 CONFIG_USE_BOOTARGS=y
 CONFIG_BOOTARGS="console=tty0 console=ttyS0,115200"
 CONFIG_SYS_DEVICE_NULLDEV=y