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/taurus_defconfig b/configs/taurus_defconfig
index 1568714..79ceebe 100644
--- a/configs/taurus_defconfig
+++ b/configs/taurus_defconfig
@@ -41,6 +41,7 @@
 CONFIG_BOARD_EARLY_INIT_F=y
 CONFIG_SPL_MAX_SIZE=0x3e00
 CONFIG_SPL_PAD_TO=0x20000
+CONFIG_SPL_BSS_MAX_SIZE=0x600
 # CONFIG_SPL_LEGACY_IMAGE_FORMAT is not set
 CONFIG_SPL_SYS_MALLOC_SIMPLE=y
 CONFIG_SPL_CRC32=y