driver core: Fix handling of SYNC_STATE_ONLY + STATELESS device links

Commit 21c27f06 ("driver core: Fix SYNC_STATE_ONLY device link
implementation") didn't completely fix STATELESS + SYNC_STATE_ONLY
handling.

What looks like an optimization in that commit is actually a bug that
causes an if condition to always take the else path. This prevents
reordering of devices in the dpm_list when a DL_FLAG_STATELESS device
link is create on top of an existing DL_FLAG_SYNC_STATE_ONLY device
link.

Fixes: 21c27f06 ("driver core: Fix SYNC_STATE_ONLY device link implementation")
Signed-off-by: Saravana Kannan <saravanak@google.com>
Cc: stable <stable@vger.kernel.org>
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Link: https://lore.kernel.org/r/20200520043626.181820-1-saravanak@google.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/base/core.c

@@ -360,12 +360,14 @@ struct device_link *device_link_add(struct device *consumer,
 
 		if (flags & DL_FLAG_STATELESS) {
 			kref_get(&link->kref);
-			link->flags |= DL_FLAG_STATELESS;
 			if (link->flags & DL_FLAG_SYNC_STATE_ONLY &&
-			    !(link->flags & DL_FLAG_STATELESS))
+			    !(link->flags & DL_FLAG_STATELESS)) {
+				link->flags |= DL_FLAG_STATELESS;
 				goto reorder;
-			else
+			} else {
+				link->flags |= DL_FLAG_STATELESS;
 				goto out;
+			}
 		}
 
 		/*