Currently when there are SR-IOV VF(s) and the user does "ip link show <pf
interface>" the VF unicast MAC addresses all show 00:00:00:00:00:00
if the unicast MAC was set via VIRTCHNL (i.e. not administratively set
by the host PF).

This is misleading to the host administrator. Fix this by setting the
VF's dflt_lan_addr.addr when the VF's unicast MAC address is
configured via VIRTCHNL. There are a couple cases where we don't allow
the dflt_lan_addr.addr field to be written. First, If the VF's
pf_set_mac field is true and the VF is not trusted, then we don't allow
the dflt_lan_addr.addr to be modified. Second, if the
dflt_lan_addr.addr has already been set (i.e. via VIRTCHNL).

Also a small refactor was done to separate the flow for add and delete
MAC addresses in order to simplify the logic for error conditions
and set/clear the VF's dflt_lan_addr.addr field.
Signed-off-by: Brett Creeley <brett.creeley@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>