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: NMatti Vaittinen <matti.vaittinen@fi.rohmeurope.com>
Acked-by: NScott Branden <scott.branden@broadcom.com>
Reviewed-by: NGrygorii Strashko <grygorii.strashko@ti.com>
Reviewed-by: NMichal Simek <michal.simek@xilinx.com>
Reviewed-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Acked-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: NWilliam Breathitt Gray <vilhelm.gray@gmail.com>
Acked-by: NKuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>