IB: Convert msleep below 20ms to usleep_range

The msleep(1) may do not sleep 1 ms as expected
and will sleep longer. The simple conversion from
msleep to usleep_range between 1ms and 2ms can solve an
issue.

The full and comprehensive explanation can be found at [1] and [2].

[1] https://lkml.org/lkml/2007/8/3/250
[2] Documentation/timers/timers-howto.txt

Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Reviewed-by: Erez Shitrit <erezsh@mellanox.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>
diff --git a/drivers/infiniband/hw/mlx4/mcg.c b/drivers/infiniband/hw/mlx4/mcg.c
index 3405e94..b73f897 100644
--- a/drivers/infiniband/hw/mlx4/mcg.c
+++ b/drivers/infiniband/hw/mlx4/mcg.c
@@ -1091,7 +1091,7 @@
 		if (!count)
 			break;
 
-		msleep(1);
+		usleep_range(1000, 2000);
 	} while (time_after(end, jiffies));
 
 	flush_workqueue(ctx->mcg_wq);