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/mx7ulp_com_defconfig b/configs/mx7ulp_com_defconfig
index 62992fe..b382b57 100644
--- a/configs/mx7ulp_com_defconfig
+++ b/configs/mx7ulp_com_defconfig
@@ -8,6 +8,7 @@
 CONFIG_DEFAULT_DEVICE_TREE="imx7ulp-com"
 CONFIG_LDO_ENABLED_MODE=y
 CONFIG_TARGET_MX7ULP_COM=y
+CONFIG_SYS_LOAD_ADDR=0x60800000
 CONFIG_SYS_EXTRA_OPTIONS="IMX_CONFIG=board/ea/mx7ulp_com/imximage.cfg"
 CONFIG_DEFAULT_FDT_FILE="imx7ulp-com"
 CONFIG_BOARD_EARLY_INIT_F=y