x86/amd-iommu: fix broken check in amd_iommu_flush_all_devices

The amd_iommu_pd_table is indexed by protection domain
number and not by device id. So this check is broken and
must be removed.

Cc: stable@kernel.org
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>