GPIO fixes for v4.8: This fixes a Kconfig issue with UM: when I made GPIOLIB available to all archs, that included UM, but the OF part of GPIOLIB requires HAS_IOMEM, so we add HAS_IOMEM as a dependency to OF_GPIO. This in turn exposed the fact that a few GPIO drivers were implicitly assuming OF_GPIO as their dependency but instead depended on OF alone (the typical problem being a pointer inside gpio_chip not existing unless OF_GPIO is selected) and then UM would fail to compile with these drivers instead. Then I lost patience and made any GPIO driver depending on just OF depend on OF_GPIO instead, that is certainly what they meant and the only thing that makes sense anyway. GPIO with just OF but !OF_GPIO does not make sense. Also a fix for the max730x driver data pointer, and a minor comment fix for the GPIO tools.