util/futility: trivial - Add distclean target

The what-jenkins-does build runs distclean when building the utilities.
It doesn't fail the build if distclean fails, but it generates a
scary warning.

Change-Id: Iac90958951976ed326a89ef2b5f2d9f17f9f2d6b
Signed-off-by: Martin Roth <martinroth@google.com>
Reviewed-on: https://review.coreboot.org/13888
Tested-by: build bot (Jenkins)
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>
1 file changed