amd_iommu: Use correct bitmask to set capability BAR

amd_iommu: Use correct bitmask to set capability BAR

AMD IOMMU provides the base address of control registers through
IVRS table and PCI capability. Since this base address is of 64 bit,
use 32 bits mask (instead of 16 bits) to set BAR low and high.

Fixes: d29a09ca68 ("hw/i386: Introduce AMD IOMMU")
Signed-off-by: Sairaj Kodilkar <sarunkod@amd.com>
Reviewed-by: Vasant Hegde <vasant.hegde@amd.com>
Message-Id: <20250207045354.27329-3-sarunkod@amd.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
(cherry picked from commit 3684717b7407cc395dc9bf522e193dbc85293dee)
(Mjt: adjust for 7.2.x)
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>