irqchip: Make irq-msi-lib.h globally available

Move irq-msi-lib.h into include/linux/irqchip, making it available
to compilation units outside of drivers/irqchip.

This requires some churn in drivers to fetch it from the new location,
generated using this script:

	git grep -l -w \"irq-msi-lib.h\" | \
	xargs sed -i -e 's:"irq-msi-lib.h":\<linux/irqchip/irq-msi-lib.h\>:'

Signed-off-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/all/20250513172819.2216709-2-maz@kernel.org