ibmvnic: notify peers when failover and migration happen

Commit 61d3e1d9 ("ibmvnic: Remove netdev notify for failover resets")
excluded the failover case for notify call because it said
netdev_notify_peers() can cause network traffic to stall or halt.
Current testing does not show network traffic stall
or halt because of the notify call for failover event.
netdev_notify_peers may be used when a device wants to inform the
rest of the network about some sort of a reconfiguration
such as failover or migration.

It is unnecessary to call that in other events like
FATAL, NON_FATAL, CHANGE_PARAM, and TIMEOUT resets
since in those scenarios the hardware does not change.
If the driver must do a hard reset, it is necessary to notify peers.

Fixes: 61d3e1d9

 ("ibmvnic: Remove netdev notify for failover resets")
Suggested-by: Brian King <brking@linux.vnet.ibm.com>
Suggested-by: Pradeep Satyanarayana <pradeeps@linux.vnet.ibm.com>
Signed-off-by: Dany Madden <drt@linux.ibm.com>
Signed-off-by: Lijun Pan <ljp@linux.ibm.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>