Staging: Octeon: Run phy bus accesses on a workqueue.

When directly accessing a phy, we must acquire the mdio bus lock.  To
do that we cannot be in interrupt context, so we need to move these
operations to a workqueue.

Signed-off-by: David Daney <ddaney@caviumnetworks.com>
To: linux-mips@linux-mips.org
To: netdev@vger.kernel.org
To: gregkh@suse.de
Patchwork: http://patchwork.linux-mips.org/patch/965/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>