bonding: Fix initialize after use for 3ad machine state spinlock

The 3ad machine state spinlock can be used before it is inititialized
while doing bond_enslave() (and the port is being initialized) since
port->slave is set before the lock is prepared, thus causing soft
lock-ups and a multitude of other nasty bugs.

[ Rename __initialize_port_locks() variable name to 'slave' -DaveM ]

Signed-off-by: Nikolay Aleksandrov <nikolay@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>