Merge branch irq/gpio-immutable into irq/irqchip-next

* irq/gpio-immutable:
  : .
  : First try at preventing the GPIO subsystem from abusing irq_chip
  : data structures. The general idea is to have an irq_chip flag
  : to tell the GPIO subsystem that these structures are immutable,
  : and to convert drivers one by one.
  : .
  Documentation: Update the recommended pattern for GPIO irqchips
  gpio: Update TODO to mention immutable irq_chip structures
  pinctrl: amd: Make the irqchip immutable
  pinctrl: msmgpio: Make the irqchip immutable
  pinctrl: apple-gpio: Make the irqchip immutable
  gpio: pl061: Make the irqchip immutable
  gpio: tegra186: Make the irqchip immutable
  gpio: Add helpers to ease the transition towards immutable irq_chip
  gpio: Expose the gpiochip_irq_re[ql]res helpers
  gpio: Don't fiddle with irqchips marked as immutable

Signed-off-by: Marc Zyngier <maz@kernel.org>