pciehp: update workqueue usage

* Rename pciehp_wq to pciehp_ordered_wq and add non-ordered pciehp_wq
  which is used instead of the system workqueue.  This is to remove
  the use of flush_scheduled_work() which is deprecated and scheduled
  for removal.

* With cmwq in place, there's no point in creating workqueues lazily.
  Create both pciehp_wq and pciehp_ordered_wq upfront.

* Include workqueue.h from pciehp.h.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Jesse Barnes <jbarnes@virtuousgeek.org>
diff --git a/drivers/pci/hotplug/pciehp_ctrl.c b/drivers/pci/hotplug/pciehp_ctrl.c
index 8f58148..085dbb5 100644
--- a/drivers/pci/hotplug/pciehp_ctrl.c
+++ b/drivers/pci/hotplug/pciehp_ctrl.c
@@ -32,7 +32,6 @@
 #include <linux/types.h>
 #include <linux/slab.h>
 #include <linux/pci.h>
-#include <linux/workqueue.h>
 #include "../pci.h"
 #include "pciehp.h"
 
@@ -50,7 +49,7 @@
 	info->p_slot = p_slot;
 	INIT_WORK(&info->work, interrupt_event_handler);
 
-	schedule_work(&info->work);
+	queue_work(pciehp_wq, &info->work);
 
 	return 0;
 }
@@ -345,7 +344,7 @@
 		kfree(info);
 		goto out;
 	}
-	queue_work(pciehp_wq, &info->work);
+	queue_work(pciehp_ordered_wq, &info->work);
  out:
 	mutex_unlock(&p_slot->lock);
 }
@@ -378,7 +377,7 @@
 		if (ATTN_LED(ctrl))
 			pciehp_set_attention_status(p_slot, 0);
 
-		schedule_delayed_work(&p_slot->work, 5*HZ);
+		queue_delayed_work(pciehp_wq, &p_slot->work, 5*HZ);
 		break;
 	case BLINKINGOFF_STATE:
 	case BLINKINGON_STATE:
@@ -440,7 +439,7 @@
 	else
 		p_slot->state = POWERON_STATE;
 
-	queue_work(pciehp_wq, &info->work);
+	queue_work(pciehp_ordered_wq, &info->work);
 }
 
 static void interrupt_event_handler(struct work_struct *work)