drm/i915/selftests: Be a little more lenient for reset workers

Give the reset worker a kick before losing help when waiting for hang
recovery, as the CPU scheduler is a little unreliable.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200227085723.1961649-15-chris@chris-wilson.co.uk