iommu/amd: Fix interrupt remapping for aliased devices

An apparent cut and paste error prevents the correct flags from being
set on the alias device resulting in MSI on conventional PCI devices
failing to work.  This also produces error events from the IOMMU like:

AMD-Vi: Event logged [INVALID_DEVICE_REQUEST device=00:14.4 address=0x000000fdf8000000 flags=0x0a00]

Where 14.4 is a PCIe-to-PCI bridge with a device behind it trying to
use MSI interrupts.

Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Joerg Roedel <joro@8bytes.org>