New ARMADA ethernet driver

[SUENAGA Hiroki <hsuenaga%netbsd.org@localhost>]

Hi,

I implement a new MARVELL ARMADA's ethernet dirver using 'counter mode.'
if_mvgbe is still working, but registers used by if_mvgbe is not
described in reference manual, so I think using new mode is better.
It's hard to maintain the undescribed features...

The driver is stable for my MIRABOX. If you are interested in,
add 'mvxpe* at mvsoc?' to your -current's kernel config. MAC addresses
are passed from u-boot's command line. for example,

  bootm $loadaddr ethaddr=01:02:03:04:05:06 eth1addr=11:22:33:44:55:66

this is common arugument of u-boot.

Thank you,
-- 
SUENAGA Hiroki <hsuenaga%netbsd.org@localhost>