gpio: nomadik: fix the debugfs helper stub

gpio: nomadik: fix the debugfs helper stub

Commit ddeb66d2cb10 ("gpio: nomadik: don't print out global GPIO numbers
in debugfs callbacks") failed to also update the stub of the debugfs
helper for !CONFIG_DEBUG_FS. Fix the resulting build failure.

Fixes: ddeb66d2cb10 ("gpio: nomadik: don't print out global GPIO numbers in debugfs callbacks")
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202509132232.12viPUPB-lkp@intel.com/
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20250915091007.28438-1-brgl@bgdev.pl
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>