drm/i915: remember to call i915_sw_fence_fini

Seems to fix some object-debug splat which appeared while debugging
something unrelated.

v2: s/guc_blocked/guc_state.blocked/
Signed-off-by: Matthew Auld <matthew.auld@intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Matthew Brost <matthew.brost@intel.com>
Tested-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Matthew Brost <matthew.brost@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210924144646.4096402-1-matthew.auld@intel.com

drivers/gpu/drm/i915/gt/intel_context.c

@@ -419,6 +419,7 @@ void intel_context_fini(struct intel_context *ce)
 
 	mutex_destroy(&ce->pin_mutex);
 	i915_active_fini(&ce->active);
+	i915_sw_fence_fini(&ce->guc_state.blocked);
 }
 
 void i915_context_module_exit(void)