dkms updates

dkms (which now actually attempts to compile kernel modules) shows an autopkgtest regression in lime-forensics due to an outdated autopkgtest control entry. Let's just switch to autopkgtest-pkg-dkms and have autodep8 generate the current form of the test control file with all flags and dependencies. While we are at it, switch to dh-sequence-dkms, s.t. I can later split off a dh-dkms package from the current dkms binary package without affecting its build rdepends.