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/main.c b/drivers/infiniband/hw/mlx4/main.c
index 75b2f7d..d1b43cb 100644
--- a/drivers/infiniband/hw/mlx4/main.c
+++ b/drivers/infiniband/hw/mlx4/main.c
@@ -1155,7 +1155,7 @@ static void mlx4_ib_disassociate_ucontext(struct ib_ucontext *ibcontext)
 			 * call to mlx4_ib_vma_close.
 			 */
 			put_task_struct(owning_process);
-			msleep(1);
+			usleep_range(1000, 2000);
 			owning_process = get_pid_task(ibcontext->tgid,
 						      PIDTYPE_PID);
 			if (!owning_process ||