drm/i915/guc: Hook GuC scheduling policies up

Use the official driver default scheduling policies for configuring
the GuC scheduler rather than a bunch of hardcoded values.

v2:
 (Matthew Brost)
  - Move I915_ENGINE_WANT_FORCED_PREEMPTION to later patch

Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
Signed-off-by: Matthew Brost <matthew.brost@intel.com>
Reviewed-by: Matthew Brost <matthew.brost@intel.com>
Cc: Jose Souza <jose.souza@intel.com>
Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210727002348.97202-21-matthew.brost@intel.com