drm/i915: Verify power domains state during suspend in all cases

There is no reason why we couldn't verify the power domains state during
suspend in all cases, so do that. I overlooked this when originally
adding the check.

Cc: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Imre Deak <imre.deak@intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20190509173446.31095-4-imre.deak@intel.com