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/evb-rk3308_defconfig b/configs/evb-rk3308_defconfig
index bd4a03a..5e5d6dc 100644
--- a/configs/evb-rk3308_defconfig
+++ b/configs/evb-rk3308_defconfig
@@ -13,6 +13,7 @@
 CONFIG_DEBUG_UART_BASE=0xFF0C0000
 CONFIG_DEBUG_UART_CLOCK=24000000
 CONFIG_DEBUG_UART=y
+CONFIG_SYS_LOAD_ADDR=0xc00800
 CONFIG_ANDROID_BOOT_IMAGE=y
 CONFIG_FIT=y
 CONFIG_FIT_VERBOSE=y