Driver maintains its primary MAC in a private field which
gets updated when ndo_dev_set_mac() gets called.

However, there are flows where the primary MAC of the device can change
without said NDO being called [bond device in TLB mode configuring
slaves' addresses], resulting in a configuration where there's a mismatch
between what's apparent to user [the netdevice's value] and what's
configured in the HW [the private value].

As we don't have any real motivation of maintaining this
private field, simply remove it and start using the netdevice's
field instead.
Signed-off-by: NYuval Mintz <Yuval.Mintz@cavium.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>