drm/i915: Construct a request even if the GPU is currently hung

drm/i915: Construct a request even if the GPU is currently hung

As we now have the ability to directly reset the GPU from the waiter
(and so do not need to drop the lock in order to let the reset proceed)
and also do not lose requests over a reset, we can now simply queue the
request to occur after the reset rather than roundtripping to userspace
(or worse failing with EIO).

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: http://patchwork.freedesktop.org/patch/msgid/20170114162334.10271-1-chris@chris-wilson.co.uk
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>