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/socfpga_n5x_atf_defconfig b/configs/socfpga_n5x_atf_defconfig
index dc4734b..e1dddf9 100644
--- a/configs/socfpga_n5x_atf_defconfig
+++ b/configs/socfpga_n5x_atf_defconfig
@@ -25,6 +25,7 @@
 CONFIG_USE_BOOTCOMMAND=y
 CONFIG_BOOTCOMMAND="run fatscript; run mmcfitload; run mmcfitboot"
 CONFIG_SPL_MAX_SIZE=0x40000
+CONFIG_SPL_BSS_MAX_SIZE=0x100000
 CONFIG_SPL_CRC32=y
 CONFIG_SPL_CACHE=y
 CONFIG_SPL_SPI_LOAD=y