irqchip/mvebu-pic: Switch to dynamic chip name output

Instead of overriding the name field, track the corresponding device
and use the relevant callback to output its name.

This allows us to make the irq_chip structure const.

Signed-off-by: Marc Zyngier <maz@kernel.org>
Reviewed-by: Gregory CLEMENT <gregory.clement@bootlin.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20220209162607.1118325-6-maz@kernel.org