emulation/qemu-i440fx,q35: Split chromeos.c

This drops VBOOT_NO_BOARD_SUPPORT.

There is little impact of always having recovery_mode_switch()
implemented in bootmode.c. A weak write_protect_state() is not
necessary as there is no BOOT_DEVICE_SPI_FLASH with the emulation.
Call to fill_lb_gpios() is already guarded with CONFIG(CHROMEOS)
so the weak implementation would not be referenced.

Change-Id: I3c00b30c5233ae3556b7622f97c3166668c8ab12
Signed-off-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/58946
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Julius Werner <jwerner@chromium.org>

src/mainboard/emulation/qemu-i440fx/Kconfig

@@ -21,7 +21,6 @@ config VBOOT
 	select VBOOT_MUST_REQUEST_DISPLAY
 	select VBOOT_STARTS_IN_BOOTBLOCK
 	select VBOOT_VBNV_CMOS
-	select VBOOT_NO_BOARD_SUPPORT
 	select GBB_FLAG_DISABLE_LID_SHUTDOWN
 	select GBB_FLAG_DISABLE_PD_SOFTWARE_SYNC
 	select GBB_FLAG_DISABLE_EC_SOFTWARE_SYNC