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/j721e_evm_r5_defconfig b/configs/j721e_evm_r5_defconfig
index 45bebbe..3b4c1e1 100644
--- a/configs/j721e_evm_r5_defconfig
+++ b/configs/j721e_evm_r5_defconfig
@@ -29,6 +29,7 @@
 CONFIG_USE_BOOTCOMMAND=y
 # CONFIG_DISPLAY_CPUINFO is not set
 CONFIG_SPL_MAX_SIZE=0xc0000
+CONFIG_SPL_BSS_MAX_SIZE=0xa000
 CONFIG_SPL_BOARD_INIT=y
 CONFIG_SPL_STACK_R=y
 CONFIG_SPL_SEPARATE_BSS=y