net: sunhme: output link status with a single print.

This driver currently prints the link status using four separate
printk calls, which these days gets presented to the user as four
distinct messages, not exactly ideal:

  [   32.582778] eth0: Link is up using
  [   32.582828] internal
  [   32.582837] transceiver at
  [   32.582888] 100Mb/s, Full Duplex.

Restructure the display_link_mode function to use a single netdev_info
call to present all this information as a single message, which is much
nicer:

  [   33.640143] hme 0000:00:01.1 eth0: Link is up using internal transceiver at 100Mb/s, Full Duplex.

The display_forced_link_mode function has a similar structure, so adjust
it in a similar fashion.

Signed-off-by: Nick Bowler <nbowler@draconx.ca>
Signed-off-by: David S. Miller <davem@davemloft.net>