hv_balloon: Replace spin_is_locked() with lockdep

lockdep_assert_held() is better suited to checking locking requirements,
since it won't get confused when someone else holds the lock. This is
also a step towards possibly removing spin_is_locked().
Signed-off-by: Lance Roy <ldr709@gmail.com>
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Stephen Hemminger <sthemmin@microsoft.com>
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/hv/hv_balloon.c

@@ -689,7 +689,7 @@ static void hv_page_online_one(struct hv_hotadd_state *has, struct page *pg)
 	__online_page_increment_counters(pg);
 	__online_page_free(pg);
 
-	WARN_ON_ONCE(!spin_is_locked(&dm_device.ha_lock));
+	lockdep_assert_held(&dm_device.ha_lock);
 	dm_device.num_pages_onlined++;
 }