drm/i915/guc: Preparing for GuC reset along with engine reset

Adding the call to prepare for guc reset along with engine
reset. intel_uc_reset_prepare() calls to disable guc communication
and to sanitize.

Cc: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Cc: Michal Wajdeczko <michal.wajdeczko@intel.com>
Signed-off-by: Sujaritha Sundaresan <sujaritha.sundaresan@intel.com>
Reviewed-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20190307184445.25895-1-sujaritha.sundaresan@intel.com

drivers/gpu/drm/i915/i915_reset.c

@@ -826,6 +826,8 @@ static void __i915_gem_set_wedged(struct drm_i915_private *i915)
 	for_each_engine(engine, i915, id)
 		reset_prepare_engine(engine);
 
+	intel_uc_reset_prepare(i915);
+
 	/* Even if the GPU reset fails, it should still stop the engines */
 	if (!INTEL_INFO(i915)->gpu_reset_clobbers_display)
 		intel_gpu_reset(i915, ALL_ENGINES);