IB/fmr_pool: Stop ib_fmr threads from contributing to load average

I noticed my machine was at a constant load average of 1. This was
because ib_create_fmr_pool calls kthread_create but does not
immediately wake the thread up.

Change to using kthread_run so we enter ib_fmr_cleanup_thread(), set
TASK_INTERRUPTIBLE, then go to sleep.
Signed-off-by: Roland Dreier <rolandd@cisco.com>

drivers/infiniband/core/fmr_pool.c

@@ -291,7 +291,7 @@ struct ib_fmr_pool *ib_create_fmr_pool(struct ib_pd             *pd,
 	atomic_set(&pool->flush_ser, 0);
 	init_waitqueue_head(&pool->force_wait);
 
-	pool->thread = kthread_create(ib_fmr_cleanup_thread,
+	pool->thread = kthread_run(ib_fmr_cleanup_thread,
 				   pool,
 				   "ib_fmr(%s)",
 				   device->name);