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/ci20_mmc_defconfig b/configs/ci20_mmc_defconfig
index 2337ac6..e8bcc0b 100644
--- a/configs/ci20_mmc_defconfig
+++ b/configs/ci20_mmc_defconfig
@@ -24,6 +24,7 @@
 CONFIG_MISC_INIT_R=y
 CONFIG_SYS_MALLOC_BOOTPARAMS=y
 CONFIG_SPL_MAX_SIZE=0x2e00
+CONFIG_SPL_BSS_MAX_SIZE=0x2000
 # CONFIG_SPL_BANNER_PRINT is not set
 CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_USE_SECTOR=y
 CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_SECTOR=0x1c