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/j721s2_evm_r5_defconfig b/configs/j721s2_evm_r5_defconfig
index 7f1d2b0..427dcf8 100644
--- a/configs/j721s2_evm_r5_defconfig
+++ b/configs/j721s2_evm_r5_defconfig
@@ -33,6 +33,7 @@
 CONFIG_SPL_SIZE_LIMIT_SUBTRACT_GD=y
 CONFIG_SPL_SIZE_LIMIT_SUBTRACT_MALLOC=y
 CONFIG_SPL_MAX_SIZE=0xc0000
+CONFIG_SPL_BSS_MAX_SIZE=0xa000
 CONFIG_SPL_SYS_REPORT_STACK_F_USAGE=y
 CONFIG_SPL_BOARD_INIT=y
 CONFIG_SPL_SYS_MALLOC_SIMPLE=y