workqueue: consistently use int for @cpu variables

Workqueue is mixing unsigned int and int for @cpu variables.  There's
no point in using unsigned int for cpus - many of cpu related APIs
take int anyway.  Consistently use int for @cpu variables so that we
can use negative values to mark special ones.

This patch doesn't introduce any visible behavior changes.

Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Lai Jiangshan <laijs@cn.fujitsu.com>
diff --git a/include/linux/workqueue.h b/include/linux/workqueue.h
index 5bd030f..899be66 100644
--- a/include/linux/workqueue.h
+++ b/include/linux/workqueue.h
@@ -435,7 +435,7 @@
 
 extern void workqueue_set_max_active(struct workqueue_struct *wq,
 				     int max_active);
-extern bool workqueue_congested(unsigned int cpu, struct workqueue_struct *wq);
+extern bool workqueue_congested(int cpu, struct workqueue_struct *wq);
 extern unsigned int work_busy(struct work_struct *work);
 
 /*
@@ -466,12 +466,12 @@
 }
 
 #ifndef CONFIG_SMP
-static inline long work_on_cpu(unsigned int cpu, long (*fn)(void *), void *arg)
+static inline long work_on_cpu(int cpu, long (*fn)(void *), void *arg)
 {
 	return fn(arg);
 }
 #else
-long work_on_cpu(unsigned int cpu, long (*fn)(void *), void *arg);
+long work_on_cpu(int cpu, long (*fn)(void *), void *arg);
 #endif /* CONFIG_SMP */
 
 #ifdef CONFIG_FREEZER