drm/i915/gt: Save/restore interrupts around breadcrumb disable

Stop assuming we only get called with irqs-on for disarming the
breadcrumbs, and do a full save/restore spin_lock_irq.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190813132916.20382-2-chris@chris-wilson.co.uk

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

@@ -67,14 +67,15 @@ static void __intel_breadcrumbs_disarm_irq(struct intel_breadcrumbs *b)
 void intel_engine_disarm_breadcrumbs(struct intel_engine_cs *engine)
 {
 	struct intel_breadcrumbs *b = &engine->breadcrumbs;
+	unsigned long flags;
 
 	if (!b->irq_armed)
 		return;
 
-	spin_lock_irq(&b->irq_lock);
+	spin_lock_irqsave(&b->irq_lock, flags);
 	if (b->irq_armed)
 		__intel_breadcrumbs_disarm_irq(b);
-	spin_unlock_irq(&b->irq_lock);
+	spin_unlock_irqrestore(&b->irq_lock, flags);
 }
 
 static inline bool __request_completed(const struct i915_request *rq)