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/r2dplus_defconfig b/configs/r2dplus_defconfig
index 73b2c99..ccbb082 100644
--- a/configs/r2dplus_defconfig
+++ b/configs/r2dplus_defconfig
@@ -4,6 +4,7 @@
 CONFIG_ENV_SECT_SIZE=0x40000
 CONFIG_DEFAULT_DEVICE_TREE="sh7751-r2dplus"
 CONFIG_TARGET_R2DPLUS=y
+CONFIG_SYS_LOAD_ADDR=0x8e000000
 CONFIG_BOOTDELAY=-1
 CONFIG_USE_BOOTARGS=y
 CONFIG_BOOTARGS="console=ttySC0,115200"