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/stm32746g-eval_spl_defconfig b/configs/stm32746g-eval_spl_defconfig
index c8e3052..16b8b64 100644
--- a/configs/stm32746g-eval_spl_defconfig
+++ b/configs/stm32746g-eval_spl_defconfig
@@ -27,6 +27,7 @@
 # CONFIG_DISPLAY_CPUINFO is not set
 CONFIG_BOARD_LATE_INIT=y
 CONFIG_SPL_PAD_TO=0x8000
+CONFIG_SPL_NO_BSS_LIMIT=y
 CONFIG_SPL_BOARD_INIT=y
 CONFIG_SPL_SYS_MALLOC_SIMPLE=y
 CONFIG_SPL_MTD_SUPPORT=y