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/ids8313_defconfig b/configs/ids8313_defconfig
index 91ce5ea..1cb9f5f 100644
--- a/configs/ids8313_defconfig
+++ b/configs/ids8313_defconfig
@@ -117,6 +117,7 @@
 CONFIG_ACR_RPTCNT_4=y
 CONFIG_LCRR_EADC_1=y
 CONFIG_LCRR_CLKDIV_2=y
+CONFIG_SYS_LOAD_ADDR=0x100000
 CONFIG_FIT=y
 CONFIG_FIT_SIGNATURE=y
 CONFIG_LEGACY_IMAGE_FORMAT=y