md/md-linear: cleanup linear_add()

Now that caller already suspend the array, there is no need to suspend
array in liner_add().

Note that mddev_suspend/resume() is not used anymore.

Signed-off-by: Yu Kuai <[e-mail]>
Signed-off-by: Song Liu <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]

drivers/md/md-linear.c

···
 	 * in linear_congested(), therefore kfree_rcu() is used to free
 	 * oldconf until no one uses it anymore.
 	 */
-	mddev_suspend(mddev);
 	oldconf = rcu_dereference_protected(mddev->private,
 			lockdep_is_held(&mddev->reconfig_mutex));
 	mddev->raid_disks++;
···
 	rcu_assign_pointer(mddev->private, newconf);
 	md_set_array_sectors(mddev, linear_size(mddev, 0, 0));
 	set_capacity_and_notify(mddev->gendisk, mddev->array_sectors);
-	mddev_resume(mddev);
 	kfree_rcu(oldconf, rcu);
 	return 0;
 }