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/px30-core-ctouch2-px30_defconfig b/configs/px30-core-ctouch2-px30_defconfig
index 16503ae..f704aeb 100644
--- a/configs/px30-core-ctouch2-px30_defconfig
+++ b/configs/px30-core-ctouch2-px30_defconfig
@@ -31,6 +31,7 @@
 CONFIG_MISC_INIT_R=y
 CONFIG_SPL_MAX_SIZE=0x20000
 CONFIG_SPL_PAD_TO=0x7f8000
+CONFIG_SPL_BSS_MAX_SIZE=0x4000
 CONFIG_SPL_BOOTROM_SUPPORT=y
 # CONFIG_SPL_RAW_IMAGE_SUPPORT is not set
 CONFIG_SPL_STACK_R=y