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/stm32mp15_dhcom_basic_defconfig b/configs/stm32mp15_dhcom_basic_defconfig
index 19eccec..1fae0e4 100644
--- a/configs/stm32mp15_dhcom_basic_defconfig
+++ b/configs/stm32mp15_dhcom_basic_defconfig
@@ -25,6 +25,8 @@
 CONFIG_BOOTCOMMAND="run bootcmd_stm32mp"
 CONFIG_CONSOLE_MUX=y
 CONFIG_BOARD_EARLY_INIT_F=y
+CONFIG_SPL_FOOTPRINT_LIMIT=y
+CONFIG_SPL_MAX_FOOTPRINT=0x3db00
 CONFIG_SPL_LEGACY_IMAGE_FORMAT=y
 CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_USE_PARTITION=y
 CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_PARTITION=3