pinctrl: npcm: Fix broken references to chip->parent_device

The npcm driver has a bunch of references to the irq_chip parent_device
field, but never sets it.

Fix it by fishing that reference from somewhere else, but it is
obvious that these debug statements were never used. Also remove
an unused field in a local data structure.

Signed-off-by: Marc Zyngier <maz@kernel.org>
Acked-by: Bartosz Golaszewski <brgl@bgdev.pl>
Link: https://lore.kernel.org/r/20220201120310.878267-11-maz@kernel.org