gpiolib: Simplify implementation of for_each_hwgpio_in_range()

gpiolib: Simplify implementation of for_each_hwgpio_in_range()

The whole purpose of the custom CLASS() is to have possibility
to initialise the counter variable _i to 0. This can't be done
with simple __free() macro as it will be not allowed by C language.
OTOH, the CLASS() operates with the pointers and explicit usage of
the scoped variable _data is not needed, since the pointers are kept
the same over the iterations. Simplify the implementation of
for_each_hwgpio_in_range().

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20250207151149.2119765-3-andriy.shevchenko@linux.intel.com
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>