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/imx8qxp_mek_defconfig b/configs/imx8qxp_mek_defconfig
index 19e7076..f5e03f3 100644
--- a/configs/imx8qxp_mek_defconfig
+++ b/configs/imx8qxp_mek_defconfig
@@ -18,6 +18,7 @@
 CONFIG_SPL=y
 CONFIG_SPL_LOAD_IMX_CONTAINER=y
 CONFIG_IMX_CONTAINER_CFG="board/freescale/imx8qxp_mek/uboot-container.cfg"
+CONFIG_SYS_LOAD_ADDR=0x80280000
 CONFIG_OF_SYSTEM_SETUP=y
 CONFIG_SYS_EXTRA_OPTIONS="IMX_CONFIG=board/freescale/imx8qxp_mek/imximage.cfg"
 CONFIG_BOOTDELAY=3