gpiolib: cdev: Fix reference to linereq_set_config_unlocked()

With the change to cleanup.h guards, linereq_set_config_unlocked() was
collapsed into linereq_set_config(), but documentation referencing it
was not updated to reflect that change.

Update the reference to linereq_set_config().

Signed-off-by: Kent Gibson <warthog618@gmail.com>
Link: https://lore.kernel.org/r/20240924155624.230130-1-warthog618@gmail.com


Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>