drm/i915: Fix context object leak for legacy contexts

Dynamic context pinning for LRCs introduced a leak in legacy mode.
Reinstate context unreference in i915_gem_free_request for legacy contexts.

Leak reported by i-g-t/drv_module_reload fixed by this patch.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=86507
Signed-off-by: Thomas Daniel <thomas.daniel@intel.com>
Reviewed-by: John Harrison<John.C.Harrison@Intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/i915_gem.c

@@ -2574,11 +2574,13 @@ static void i915_gem_free_request(struct drm_i915_gem_request *request)
 	list_del(&request->list);
 	i915_gem_request_remove_from_client(request);
 
-	if (i915.enable_execlists && ctx) {
-		struct intel_engine_cs *ring = request->ring;
+	if (ctx) {
+		if (i915.enable_execlists) {
+			struct intel_engine_cs *ring = request->ring;
 
-		if (ctx != ring->default_context)
-			intel_lr_context_unpin(ring, ctx);
+			if (ctx != ring->default_context)
+				intel_lr_context_unpin(ring, ctx);
+		}
 		i915_gem_context_unreference(ctx);
 	}
 	kfree(request);