Convert CONFIG_SPL_BSS_MAX_SIZE et al to Kconfig

This converts the following to Kconfig:
   CONFIG_SPL_BSS_MAX_SIZE
   CONFIG_SPL_MAX_FOOTPRINT

Note that the da850evm platforms were violating the "only use one" rule
here, and so now hard-code their BSS limit.

Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/configs/cl-som-imx7_defconfig b/configs/cl-som-imx7_defconfig
index 7e872fa..af7fb37 100644
--- a/configs/cl-som-imx7_defconfig
+++ b/configs/cl-som-imx7_defconfig
@@ -26,6 +26,7 @@
 CONFIG_BOOTCOMMAND="echo SD boot attempt ...; run sdbootscript; run sdboot; echo eMMC boot attempt ...; run emmcbootscript; run emmcboot; echo USB boot attempt ...; run usbbootscript; "
 CONFIG_BOARD_LATE_INIT=y
 CONFIG_SPL_MAX_SIZE=0xe000
+CONFIG_SPL_BSS_MAX_SIZE=0x100000
 CONFIG_SPL_BOARD_INIT=y
 CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_SECTOR=0x80
 CONFIG_SPL_I2C=y