MAC_FMT had only one user and we tried to get rid of
that, but this created more problems than it solved.
As a result, this reverts three commits:
235365f3aa ("net/8021q/vlan_dev.c: Use
print_mac."), fea5fa875e ("[NET]: Remove
MAC_FMT"), and 8f789c4844 ("[NET]:
Elminate spurious print_mac() calls.")
Signed-off-by: David S. Miller <davem@davemloft.net>