Drivers should call gpiochip_lock_as_irq (which prevents the pin
direction from being changed) in their irq_request_resources callbacks
but some drivers currently fail to do so.
Instead a second, explicit and often redundant call to lock-as-irq is
made by the sysfs-interface implementation after an irq has been
requested.
Move the explicit call before the irq-request to match the unlock done
after the irq is later released. Note that this also fixes an irq leak,
should the explicit call ever have failed.
Also add a comment about removing the redundant call once the broken
drivers have been fixed.