pinctrl: armada-37xx: use raw spinlocks for regmap to avoid invalid wait context

The irqchip->irq_set_type method is called by __irq_set_trigger() under
the desc->lock raw spinlock.

The armada-37xx implementation, armada_37xx_irq_set_type(), uses an MMIO
regmap created by of_syscon_register(), which uses plain spinlocks
(the kind that are sleepable on RT).

Therefore, this is an invalid locking scheme for which we get a kernel
splat stating just that ("[ BUG: Invalid wait context ]"), because the
context in which the plain spinlock may sleep is atomic due to the raw
spinlock. We need to go raw spinlocks all the way.

Make this driver create its own MMIO regmap, with use_raw_spinlock=true,
and stop relying on syscon to provide it.

This patch depends on commit 67021f25 ("regmap: teach regmap to use
raw spinlocks if requested in the config").

Cc: <stable@vger.kernel.org> # 5.15+
Fixes: 2f227605

 ("pinctrl: armada-37xx: Add irqchip support")
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Link: https://lore.kernel.org/r/20220716233745.1704677-3-vladimir.oltean@nxp.com
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>