The board vendor and model are sometimes specified as arguments during
an internal flash, so make sure they are freed at the end of
initialization.

Change-Id: I9f43708f3b075896be67acec114bc6f390f8c6ca
Signed-off-by: Jacob Garber <jgarber1@ualberta.ca>
Found-by: Coverity CID 1230664, 1230665
Reviewed-on: https://review.coreboot.org/c/flashrom/+/34846


Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: David Hendricks <david.hendricks@gmail.com>