ChromeOS mainboards: Move more Kconfig symbols under CHROMEOS

Move the CHROMEOS dependent symbols VIRTUAL_DEV_SWITCH and
VBOOT_DYNAMIC_WORK_BUFFER under the CHROMEOS config options for the
mainboards that use them.

Change-Id: Iad126cf045cb3a312319037aff3c4b1f15f6529d
Signed-off-by: Martin Roth <martinroth@google.com>
Reviewed-on: http://review.coreboot.org/11336
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-by: Patrick Georgi <pgeorgi@google.com>
Tested-by: build bot (Jenkins)
32 files changed