PCI: aardvark: Make msi_domain_info structure a static driver structure

Make Aardvark's msi_domain_info structure into a private driver structure.
Domain info is same for every potential instatination of a controller.

Link: https://lore.kernel.org/r/20220110015018.26359-8-kabel@kernel.org


Signed-off-by: Marek Behún <kabel@kernel.org>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>