gpio: remove misleading documentation

It is currently debated where the functions to lock a certain
GPIO line as used for IRQs should be called. Delete all
misleading documentation.

Reported-by: Thomas Gleixner <[e-mail]>
Cc: Jean-Jacques Hiblot <[e-mail]>
Acked-by: Alexandre Courbot <[e-mail]>
Signed-off-by: Linus Walleij <[e-mail]>

drivers/gpio/gpiolib.c

···
  * @gpio: the GPIO line to lock as used for IRQ
  *
  * This is used directly by GPIO drivers that want to lock down
- * a certain GPIO line to be used as IRQs, for example in the
- * .to_irq() callback of their gpio_chip, or in the .irq_enable()
- * of its irq_chip implementation if the GPIO is known from that
- * code.
+ * a certain GPIO line to be used for IRQs.
  */
 int gpiod_lock_as_irq(struct gpio_desc *desc)
 {