Revert "drm/i915/guc: Disable global reset"

We have now prepared the guc reset paths to avoid taking struct_mutex, or
any other lock, and so it is now safe to re-enable.

References: fe62365f ("drm/i915/guc: Disable global reset")
Signed-off-by: Fernando Pacheco <fernando.pacheco@intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20190419230015.18121-5-fernando.pacheco@intel.com

drivers/gpu/drm/i915/i915_reset.c

@@ -641,9 +641,6 @@ int intel_gpu_reset(struct drm_i915_private *i915,
 
 bool intel_has_gpu_reset(struct drm_i915_private *i915)
 {
-	if (USES_GUC(i915))
-		return false;
-
 	if (!i915_modparams.reset)
 		return NULL;