mb/google/rambi: Drop ChromeOS support

There is an ongoing effort to deprecate VBOOT_VBNV_CMOS [1] and replace
with VBOOT_VBNV_FLASH. However, the rambi's CAR is too small for early
flash access in romstage:

/usr/local/google/home/yupingso/projects/coreboot/util/crossgcc/xgcc/bin/i386-elf-ld.bfd:
Cache as RAM area is too full
/usr/local/google/home/yupingso/projects/coreboot/util/crossgcc/xgcc/bin/i386-elf-ld.bfd:
section .car.mrc_var VMA [00000000fe008000,00000000fe00ffff] overlaps
section .car.data VMA [00000000fe000000,00000000fe008787]
make: *** [src/arch/x86/Makefile.inc:194:
coreboot-builds/GOOGLE_RAMBI/cbfs/fallback/romstage.debug] Error 1

More precisely, DCACHE_RAM_SIZE is 0x8000, and the current .car.data
size is 0x76c0. If BOOT_DEVICE_SPI_FLASH_NO_EARLY_WRITES is unselected,
then the _bss region will increase by 0x10c8 bytes (for global variables
such as `elog_mirror_buf` and `sfg`), so that .car.data will exceed
0x8000.

Since rambi has reached its AUE (2021-09-01), disable
MAINBOARD_HAS_CHROMEOS and VBOOT configs.

[1] https://issuetracker.google.com/issues/235293589

BUG=b:235293589
TEST=./util/abuild/abuild -t GOOGLE_RAMBI -a
TEST=./util/abuild/abuild -x -t GOOGLE_RAMBI -a

Change-Id: Id56795dd0653784b4d7141142ebef0b19a46ddc3
Signed-off-by: Yu-Ping Wu <yupingso@chromium.org>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/71545
Reviewed-by: Yidi Lin <yidilin@google.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Martin L Roth <gaumless@gmail.com>
diff --git a/src/mainboard/google/rambi/Kconfig b/src/mainboard/google/rambi/Kconfig
index f8af00f..49c0631 100644
--- a/src/mainboard/google/rambi/Kconfig
+++ b/src/mainboard/google/rambi/Kconfig
@@ -8,7 +8,6 @@
 	select HAVE_ACPI_TABLES
 	select HAVE_OPTION_TABLE
 	select HAVE_SPD_IN_CBFS
-	select MAINBOARD_HAS_CHROMEOS
 	select MEMORY_MAPPED_TPM
 	select MAINBOARD_HAS_TPM1
 	select SOC_INTEL_BAYTRAIL
@@ -92,11 +91,6 @@
 
 if BOARD_GOOGLE_BASEBOARD_RAMBI
 
-config VBOOT
-	select EC_GOOGLE_CHROMEEC_SWITCHES
-	select VBOOT_LID_SWITCH
-	select VBOOT_VBNV_CMOS
-
 config MAINBOARD_DIR
 	default "google/rambi"