gpiolib: Move GPIO_DYNAMIC_* constants to its only user

gpiolib: Move GPIO_DYNAMIC_* constants to its only user

There is no need to export GPIO_DYNAMIC_* constants, especially via
legacy header which is subject to remove. Move the mentioned constants
to its only user, i.e. gpiolib.c.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20250531195801.3632110-3-andriy.shevchenko@linux.intel.com
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>