gpio: merrifield: Don't use GPIOF_DIR_IN / GPIOF_DIR_OUT

The mentioned flags are dedicated solely for consumer API.
Replace them by explicit values.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
[Made a !bang clamp to (0,1) instead of infix ? operator]
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>