NetXen: Fixes for Power PC architecture

NetXen: Fix PPC architecture specific bugs
Fixes some issues seen on Big endian machines.

Signed-off by: Milan Bag <mbag@netxen.com>
Signed-off by: Mithlesh Thukral <mithlesh@netxen.com>

Signed-off-by: Jeff Garzik <jeff@garzik.org>