The USB4 (TBT) PCIe tunneling functionality triggers a lockdep warning.
That is a false-positive according to the TBT maintainer, however there
is no patch available to solve the lockdep issue. It does however
disable lockdep checks for everything else (and aborts CI runs as the
lockdep happens during boot-up).

The above issue only affects machines with a TBT dock connected, however
that's an important thing to test, so disable PCIe tunneling until the
lockdep issue is solved. This is ok, since iGFX CI doesn't need to test
PCIe tunneling.

References: https://intel-gfx-ci.01.org/tree/drm-tip/Trybot_134314v1/bat-mtlp-9/boot0.txt
Signed-off-by: Imre Deak <imre.deak@intel.com>