iommu/vt-d: debugfs: Avoid dumping context command register

iommu/vt-d: debugfs: Avoid dumping context command register

The register-based cache invalidation interface is in the process of being
replaced by the queued invalidation interface. The VT-d architecture
allows hardware implementations with a queued invalidation interface to
not implement the registers used for cache invalidation. Currently, the
debugfs interface dumps the Context Command Register unconditionally,
which is not reasonable.

Remove it to avoid potential access to non-present registers.

Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Link: https://lore.kernel.org/r/20250917025051.143853-1-baolu.lu@linux.intel.com
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>