It's hard for occasional GPIO code reader/writer to know if values 0/1
equal to IN or OUT. Use defined GPIO_LINE_DIRECTION_IN and
GPIO_LINE_DIRECTION_OUT to help them out.

NOTE - for gpio-amd-fch and gpio-bd9571mwv:
This commit also changes the return value for direction get to equal 1
for direction INPUT. Prior this commit these drivers might have
returned some other positive value but 1 for INPUT.

Signed-off-by: Matti Vaittinen <matti.vaittinen@fi.rohmeurope.com>
Acked-by: Scott Branden <scott.branden@broadcom.com>
Reviewed-by: Grygorii Strashko <grygorii.strashko@ti.com>
Reviewed-by: Michal Simek <michal.simek@xilinx.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: William Breathitt Gray <vilhelm.gray@gmail.com>
Acked-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

This adds support for interpreting the input and output bits of one
device on Moxtet bus as GPIOs.
This is needed for example by the SFP cage module of Turris Mox.

Link: https://lore.kernel.org/r/20190812161118.21476-5-marek.behun@nic.cz
Signed-off-by: Marek Behún <marek.behun@nic.cz>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>