amd_iommu: Fix mask to retrieve Interrupt Table Root Pointer from DTE

amd_iommu: Fix mask to retrieve Interrupt Table Root Pointer from DTE

Fix an off-by-one error in the definition of AMDVI_IR_PHYS_ADDR_MASK. The
current definition masks off the most significant bit of the Interrupt Table
Root ptr i.e. it only generates a mask with bits [50:6] set. See the AMD I/O
Virtualization Technology (IOMMU) Specification for the Interrupt Table
Root Pointer[51:6] field in the Device Table Entry format.

Cc: qemu-stable@nongnu.org
Fixes: b44159fe0078 ("x86_iommu/amd: Add interrupt remap support when VAPIC is not enabled")
Signed-off-by: Alejandro Jimenez <alejandro.j.jimenez@oracle.com>
Reviewed-by: Vasant Hegde <vasant.hegde@amd.com>
Message-Id: <20250617150427.20585-6-alejandro.j.jimenez@oracle.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
(cherry picked from commit 123cf4bdd378f746dfa2f5415ba084148dded3e3)
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>