PCI: Refactor HT advertising of NO_MSI flag

The few quirks that deal with NO_MSI tend to be copy-paste heavy.
Refactor them so that the hierarchy of conditions is slightly
cleaner.

Link: https://lore.kernel.org/r/20210330151145.997953-15-maz@kernel.org


Signed-off-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>