Linux requests the reset gpio optional by using devm_gpiod_get_optional().
We need to do this here too because the reset can be a global shared
reset line e.g. board por. We haven't such a helper so just drop the
final else path.

Fixes: 937fa50d9c ("usb: Port Microchip USB251x USB hub driver from Linux")
Signed-off-by: Marco Felsch <m.felsch@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

barebox doesn't define a CONFIG_OF kconfig option, but CONFIG_OFTREE
for the device tree handling and CONFIG_OFDEVICE for probing devices
out of the device tree.

Replace comment mentions of CONFIG_OF with mentions of either as
appropriate.

Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

Port of Linux patch https://patchwork.kernel.org/patch/10766235/

  The HW can swap the USB differential-pair (D+/D-) for each port
  separately. So the USB signals can be re-aligned with a misplaced
  USB connector on the PCB.

  Signed-off-by: Marco Felsch <m.felsch@pengutronix.de>
  Reviewed-by: Richard Leitner <richard.leitner@skidata.com>

Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

Port Microchip USB251x USB hub driver from Linux. Needed by ZII's
i.MX8MQ boards.

Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>