omap: Overo: Fix support for second ethernet port

The original patch got truncated when applied from patchwork.kernel.org
as discussed at:

http://www.mail-archive.com/linux-omap@vger.kernel.org/msg28953.html

This patch supplies the missing chunks.

Signed-off-by: Steve Sakoman <sakoman@gmail.com>
[tony@atomide.com: added more info to the patch description]
Signed-off-by: Tony Lindgren <tony@atomide.com>