drm/i915: Remove obsolete seqno parameter from 'i915_add_request'

There is no longer any need to retrieve a seqno value from an i915_add_request()
call. The calling code already knows which request structure is being processed
(it can only be ring->OLR). And as the request itself is now used in preference
to the basic seqno value, the latter is now redundant in this situation.

For: VIZ-4377
Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
Reviewed-by: Thomas Daniel <Thomas.Daniel@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/intel_overlay.c

@@ -219,7 +219,7 @@ static int intel_overlay_do_wait_request(struct intel_overlay *overlay,
 	BUG_ON(overlay->last_flip_req);
 	i915_gem_request_assign(&overlay->last_flip_req,
 					     ring->outstanding_lazy_request);
-	ret = i915_add_request(ring, NULL);
+	ret = i915_add_request(ring);
 	if (ret)
 		return ret;
 
@@ -291,7 +291,7 @@ static int intel_overlay_continue(struct intel_overlay *overlay,
 	WARN_ON(overlay->last_flip_req);
 	i915_gem_request_assign(&overlay->last_flip_req,
 					     ring->outstanding_lazy_request);
-	return i915_add_request(ring, NULL);
+	return i915_add_request(ring);
 }
 
 static void intel_overlay_release_old_vid_tail(struct intel_overlay *overlay)