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/octeontx2_96xx_defconfig b/configs/octeontx2_96xx_defconfig
index 02bb0f6..bbc5b25 100644
--- a/configs/octeontx2_96xx_defconfig
+++ b/configs/octeontx2_96xx_defconfig
@@ -14,6 +14,7 @@
 CONFIG_DEBUG_UART=y
 CONFIG_AHCI=y
 # CONFIG_SYS_MALLOC_CLEAR_ON_INIT is not set
+CONFIG_SYS_LOAD_ADDR=0x4000000
 CONFIG_FIT=y
 CONFIG_FIT_SIGNATURE=y
 CONFIG_OF_BOARD_SETUP=y