drm/i915/guc: Add preemption action to GuC firmware interface

We're using GuC action to request preemption. However, after requesting
preemption we need to wait for GuC to finish its own post-processing
before we start submitting our requests. Firmware is using shared
context to report its status.
Let's update GuC firmware interface with those new definitions.

v2: Drop unused INTEL_GUC_PREEMPT_OPTION_IMMEDIATE

Signed-off-by: Michał Winiarski <michal.winiarski@intel.com>
Cc: Jeff McGee <jeff.mcgee@intel.com>
Cc: Michal Wajdeczko <michal.wajdeczko@intel.com>
Cc: Oscar Mateo <oscar.mateo@intel.com>
Reviewed-by: Jeff McGee <jeff.mcgee@intel.com>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20171025200020.16636-5-michal.winiarski@intel.com