netxen: remove unused code

Remove code for phy access on unreleased NX2031 based quad-gig board.

NX3031 based production quad-gig boards do not require direct phy
access by driver.

Signed-off-by: Dhananjay Phadke <dhananjay@netxen.com>
Signed-off-by: David S. Miller <davem@davemloft.net>