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/eb_cpu5282_defconfig b/configs/eb_cpu5282_defconfig
index 37a552a..9bbfcf2 100644
--- a/configs/eb_cpu5282_defconfig
+++ b/configs/eb_cpu5282_defconfig
@@ -4,6 +4,7 @@
 CONFIG_ENV_SECT_SIZE=0x20000
 CONFIG_DEFAULT_DEVICE_TREE="eb_cpu5282"
 CONFIG_TARGET_EB_CPU5282=y
+CONFIG_SYS_LOAD_ADDR=0x20000
 CONFIG_SYS_EXTRA_OPTIONS="SYS_MONITOR_BASE=0xFF000400"
 CONFIG_BOOTDELAY=5
 # CONFIG_DISPLAY_BOARDINFO is not set