Fix lint test for build directories

config files are rename()d, which fails across filesystem borders.
So force temporary config files in current directory.

Change-Id: I583c2ab9a822a6f99f838778aa17ffd2d47eaed1
Signed-off-by: Patrick Georgi <patrick@georgi-clan.de>
Reviewed-on: http://review.coreboot.org/680
Tested-by: build bot (Jenkins)
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>