pinctrl: at91: fix deferred probing support

pinctrl: at91: fix deferred probing support

AT91 pinctrl deferred probing support is broken if the GPIO devices
haven't probed first and set gpio_banks to non-zero. The later condition
that only some GPIO devices haven't probed can't actually happen as
either all the GPIO devices have probed first or none of them have. Plus
the pinctrl driver has already returned -EINVAL, so it's not on the
deferred list to retry probing.

Fix this by consolidating the checking that all GPIO devices are probed.

Cc: Jean-Christophe Plagniol-Villard <plagnioj@jcrosoft.com>
Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: Nicolas Ferre <nicolas.ferre@microchip.com>
Cc: Alexandre Belloni <alexandre.belloni@bootlin.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-gpio@vger.kernel.org
Signed-off-by: Rob Herring <robh@kernel.org>
Acked-by: Ludovic Desroches <ludovic.desroches@microchip.com>
Tested-by: Nicolas Ferre <nicolas.ferre@microchip.com> # on sama5d3 xplained
Acked-by: Nicolas Ferre <nicolas.ferre@microchip.com>
Link: https://lore.kernel.org/r/20180712192222.32481-1-robh@kernel.org
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>