drm/i915/breadcrumbs: Use booleans for intel_breadcrumbs_busy()

Since commit 9b6586ae ("drm/i915: Keep a global seqno per-engine")
converted intel_breadcrumbs_busy() to reporting a single boolean, we
need only compute a boolean internally (and not needlessly compute the
flag).
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170315210726.12095-1-chris@chris-wilson.co.uk

drivers/gpu/drm/i915/intel_breadcrumbs.c

@@ -828,12 +828,12 @@ bool intel_breadcrumbs_busy(struct intel_engine_cs *engine)
 
 	if (b->irq_wait) {
 		wake_up_process(b->irq_wait->tsk);
-		busy |= intel_engine_flag(engine);
+		busy = true;
 	}
 
 	if (rcu_access_pointer(b->first_signal)) {
 		wake_up_process(b->signaler);
-		busy |= intel_engine_flag(engine);
+		busy = true;
 	}
 
 	spin_unlock_irq(&b->rb_lock);