ice: Fix error with handling of bonding MTU

When a bonded interface is destroyed, .ndo_change_mtu can be called
during the tear-down process while the RTNL lock is held.  This is a
problem since the auxiliary driver linked to the LAN driver needs to be
notified of the MTU change, and this requires grabbing a device_lock on
the auxiliary_device's dev.  Currently this is being attempted in the
same execution context as the call to .ndo_change_mtu which is causing a
dead-lock.

Move the notification of the changed MTU to a separate execution context
(watchdog service task) and eliminate the "before" notification.

Fixes: 348048e7

 ("ice: Implement iidc operations")
Signed-off-by: Dave Ertman <david.m.ertman@intel.com>
Tested-by: Jonathan Toppins <jtoppins@redhat.com>
Tested-by: Gurucharan G <gurucharanx.g@intel.com> (A Contingent worker at Intel)
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>