net/qede/base: use trust mode for forced MAC limitations

net/qede/base: use trust mode for forced MAC limitations

When trust mode is set to ON, VF can change it's MAC address
inspite PF has set a forced MAC for that VF from HV.

Earlier similar functionality is provided by module parameter
"allow_vf_mac_change_mode" of qed.

This change makes few changes in behavior of VF shadow config -
 - Let driver track the VF mac in shadow config as long as trust
  mode is OFF.
 - Once trust mode is ON, we should not care about MACs in shadow
  config (because we never intend to fall back because of lack of restore
  implementation).
 - Delete existing shadow MAC (this helps when trust mode is turned OFF,
  and VF tries to add new MAC – it won’t fail that time since we have
  a clean slate).
 - Skip addition and deletion of MACs in shadow configs.

Signed-off-by: Shahed Shaikh <shahed.shaikh@cavium.com>