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/x530_defconfig b/configs/x530_defconfig
index 6df383b..8b9dd57 100644
--- a/configs/x530_defconfig
+++ b/configs/x530_defconfig
@@ -18,6 +18,7 @@
 CONFIG_DEBUG_UART_BASE=0xd0012000
 CONFIG_DEBUG_UART_CLOCK=250000000
 CONFIG_DEBUG_UART=y
+CONFIG_SYS_LOAD_ADDR=0x1000000
 CONFIG_FIT=y
 CONFIG_FIT_VERBOSE=y
 CONFIG_SILENT_CONSOLE=y