usb: ohci-at91: use descriptor-based gpio APIs correctly

The gpiod_get* function family does not want the -gpio suffix.
Use devm_gpiod_get_index_optional instead of devm_gpiod_get_optional.
The descriptor based APIs handle active high/low automatically.
The vbus-gpios are output, request enable while getting the gpio.
Don't try to get any vbus-gpios for ports outside num-ports.

WTF? Big sigh.

Fixes: 054d4b7b

 ("usb: ohci-at91: Use descriptor-based gpio APIs")
Signed-off-by: Peter Rosin <peda@axentia.se>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>