ice: Fix KASAN error in LAG NETDEV_UNREGISTER handler

Currently, the same handler is called for both a NETDEV_BONDING_INFO
LAG unlink notification as for a NETDEV_UNREGISTER call.  This is
causing a problem though, since the netdev_notifier_info passed has
a different structure depending on which event is passed.  The problem
manifests as a call trace from a BUG: KASAN stack-out-of-bounds error.

Fix this by creating a handler specific to NETDEV_UNREGISTER that only
is passed valid elements in the netdev_notifier_info struct for the
NETDEV_UNREGISTER event.

Also included is the removal of an unbalanced dev_put on the peer_netdev
and related braces.

Fixes: 6a8b3572 ("ice: Respond to a NETDEV_UNREGISTER event for LAG")
Signed-off-by: Dave Ertman <david.m.ertman@intel.com>
Acked-by: Jonathan Toppins <jtoppins@redhat.com>
Tested-by: Sunitha Mekala <sunithax.d.mekala@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>