gpio/ml_ioh_gpio: Fix output value of ioh_gpio_direction_output()

The ioh_gpio_direction_output() function was missing a write to set the
desired output value.  The function would properly set the GPIO
direction, but not the output value.  The value would have to manually
be set with a follow up call to ioh_gpio_set().

Add the missing write so that ioh_gpio_direction_output() sets both the
GPIO direction and value.

Signed-off-by: Peter Tyser <ptyser@xes-inc.com>
Tested-by: Tomoya MORINAGA <tomoya-linux@dsn.okisemi.com>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>