drm/i915/tgl: whitelist PS_(DEPTH|INVOCATION)_COUNT

As with commit 3fe0107e, this change fixes multiple tests that are
using the invocation counts. Documentation doesn't list the workaround
for TGL but applying it fixes the tests.

Signed-off-by: Tapani Pälli <tapani.palli@intel.com>
Acked-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20191024103858.28113-2-mika.kuoppala@linux.intel.com