Convert CONFIG_BOARD_SIZE_LIMIT to Kconfig

This converts the following to Kconfig:
   CONFIG_BOARD_SIZE_LIMIT

To do this, introduce CONFIG_HAS_BOARD_SIZE_LIMIT.

Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/configs/mx53loco_defconfig b/configs/mx53loco_defconfig
index e7a4797..9b70a55 100644
--- a/configs/mx53loco_defconfig
+++ b/configs/mx53loco_defconfig
@@ -13,6 +13,8 @@
 CONFIG_DM_GPIO=y
 CONFIG_DEFAULT_DEVICE_TREE="imx53-qsb"
 # CONFIG_CMD_BMODE is not set
+CONFIG_HAS_BOARD_SIZE_LIMIT=y
+CONFIG_BOARD_SIZE_LIMIT=785408
 CONFIG_SYS_LOAD_ADDR=0x72000000
 CONFIG_SUPPORT_RAW_INITRD=y
 CONFIG_USE_BOOTCOMMAND=y