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/stemmy_defconfig b/configs/stemmy_defconfig
index f31960b..e21652d 100644
--- a/configs/stemmy_defconfig
+++ b/configs/stemmy_defconfig
@@ -3,6 +3,7 @@
 CONFIG_SYS_TEXT_BASE=0x100000
 CONFIG_NR_DRAM_BANKS=2
 CONFIG_DEFAULT_DEVICE_TREE="ste-ux500-samsung-stemmy"
+CONFIG_SYS_LOAD_ADDR=0x100000
 CONFIG_SYS_CONSOLE_INFO_QUIET=y
 CONFIG_HUSH_PARSER=y
 CONFIG_CMD_CONFIG=y