Provide version number for Debian firmware package

scripts/package/builddeb is used to create Debian packages.
Currently the firmware package always gets the same version number
irrespective of the Kernel version.
The paths inside the firmware package depend on the Kernel
version.

With the patch supplied the Kernel version becomes part of the
Debian firmware package number.

Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Cc: Ben Hutchings <ben@decadent.org.uk>
Acked-by: maximilian attems <max@stro.at>
Signed-off-by: Michal Marek <mmarek@suse.cz>