pinctrl: k230: Drop unused code

The build robot complains about unused code. Let's drop it,
this can be restored with simple git revert when needed.

Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202410021136.ie3cFM2w-lkp@intel.com/


Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/20241003-k320-unused-v1-1-72e65bc2f27b@linaro.org