net: Check CHANGEUPPER notifier return value

net: Check CHANGEUPPER notifier return value

switchdev drivers reflect the newly requested topology to hardware when
CHANGEUPPER is received, after software links were already formed.
However, the operation can fail and user will not be notified, as the
return value of the notifier is not checked.

Add this check and rollback software links if necessary.

Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
(cherry picked from commit b03804e7c3ad41c265c0ca21ddb306b252b4f99f)
Orabug: 28122104
Signed-off-by: Vijay Balakrishna <vijay.balakrishna@oracle.com>
Reviewed-by: Si-Wei Liu <si-wei.liu@oracle.com>
Reviewed-by: Shannon Nelson <shannon.nelson@oracle.com>
Signed-off-by: Brian Maly <brian.maly@oracle.com>