PCI: tegra: Use the DMA-API to get the MSI address

Since the upstream MSI memory writes are generated by downstream
devices, it is logically correct to have MSI target memory coming from
the DMA pool reserved for PCIe than from the general memory pool
reserved for CPU access to avoid PCIe DMA addresses coinciding with
MSI target address thereby raising unwanted MSI interrupts.

Enforce this behaviour by retrieving the MSI address through the DMA
API.

Limit the MSI target address to 32-bits to make it work for PCIe
endpoints that support only 32-bit MSI target address; endpoints that
support 64-bit MSI target address work with 32-bit MSI target
address too.

Signed-off-by: Vidya Sagar <vidyas@nvidia.com>
[lorenzo.pieralisi@arm.com: updated commit log]
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
Reviewed-by: Thierry Reding <treding@nvidia.com>
Acked-by: Thierry Reding <treding@nvidia.com>