As all other functions related to resetting engines are using
reset_engine.

v2: remove _request_ and use start/cancel instead (Chris)

Cc: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NMichel Thierry <michel.thierry@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170418202335.35232-3-michel.thierry@intel.comReviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>