Current IOMMU driver prints "Completion-wait Time-out" error message with
insufficient information to further debug the issue.
Enhancing the error message as following:
1. Log IOMMU PCI device ID in the error message.
2. With "amd_iommu_dump=1" kernel command line option, dump entire
command buffer entries including Head and Tail offset.
Dump the entire command buffer only on the first 'Completion-wait Time-out'
to avoid dmesg spam.