drivers/media/dvb/dvb-core/dvb_net.c: use %pM to show MAC address

Use the %pM kernel extension to display the MAC address and mask.

The only difference in the output is that the output is shown in
the usual colon-separated hex notation.

Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Cc: David S. Miller <davem@davemloft.net>
Signed-off-by: David S. Miller <davem@davemloft.net>