intel_iommu: Allow both Status Write and Interrupt Flag in QI wait

intel_iommu: Allow both Status Write and Interrupt Flag in QI wait

FreeBSD does both, and this appears to be perfectly valid. The VT-d
spec even talks about the ordering (the status write should be done
first, unsurprisingly).

We certainly shouldn't assert() and abort QEMU if the guest asks for
both.

Fixes: ed7b8fbcfb88 ("intel-iommu: add supports for queued invalidation interface")
Closes: https://gitlab.com/qemu-project/qemu/-/issues/3028
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Message-Id: <0122cbabc0adcc3cf878f5fd7834d8f258c7a2f2.camel@infradead.org>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>