PCI: aardvark: Make MSI irq_chip structures static driver structures

PCI: aardvark: Make MSI irq_chip structures static driver structures

In [1] it was agreed that we should use struct irq_chip as a global
static struct in the driver. Even though the structure currently
contains a dynamic member (parent_device), In [2] the plans to kill it
and make the structure completely static were set out.

Convert Aardvark's priv->msi_bottom_irq_chip and priv->msi_irq_chip to
static driver structure.

[1] https://lore.kernel.org/linux-pci/877dbcvngf.wl-maz@kernel.org/
[2] https://lore.kernel.org/linux-pci/874k6gvkhz.wl-maz@kernel.org/

Link: https://lore.kernel.org/r/20220110015018.26359-7-kabel@kernel.org
Signed-off-by: Marek Behún <kabel@kernel.org>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>