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/xilinx_zynqmp_mini_emmc0_defconfig b/configs/xilinx_zynqmp_mini_emmc0_defconfig
index a3d46c0..1cc3b21 100644
--- a/configs/xilinx_zynqmp_mini_emmc0_defconfig
+++ b/configs/xilinx_zynqmp_mini_emmc0_defconfig
@@ -23,6 +23,7 @@
 # CONFIG_BOARD_LATE_INIT is not set
 CONFIG_CLOCKS=y
 CONFIG_SPL_MAX_SIZE=0x40000
+CONFIG_SPL_BSS_MAX_SIZE=0x80000
 # CONFIG_CMDLINE_EDITING is not set
 # CONFIG_AUTO_COMPLETE is not set
 CONFIG_SYS_MAXARGS=64