PCI: iproc: Fix multi-MSI base vector number allocation

[ Upstream commit e673d697 ]

Commit fc54bae2 ("PCI: iproc: Allow allocation of multiple MSIs")
introduced multi-MSI support with a broken allocation mechanism (it failed
to reserve the proper number of bits from the inner domain).  Natural
alignment of the base vector number was also not guaranteed.

Link: https://lore.kernel.org/r/20210622152630.40842-1-sbodomerle@gmail.com


Fixes: fc54bae2 ("PCI: iproc: Allow allocation of multiple MSIs")
Reported-by: Pali Rohár <pali@kernel.org>
Signed-off-by: Sandor Bodo-Merle <sbodomerle@gmail.com>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Acked-by: Marc Zyngier <maz@kernel.org>
Acked-by: Pali Rohár <pali@kernel.org>
Acked-by: Ray Jui <ray.jui@broadcom.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>