arm: omap: board-overo: reset GPIO for SMSC911x

The reset GPIO should be set for the SMSC911x, otherwise the controller
will not work and probing will fail. In the case of the tobi-duo
expansion board, the second controller shares the same GPIO, thus no
more changes are required (not tested).

Signed-off-by: Florian Vaussard <florian.vaussard@epfl.ch>
Signed-off-by: Tony Lindgren <tony@atomide.com>