iommu/vt-d: Remove scalabe mode in domain_context_clear_one()

domain_context_clear_one() only handles the context entry teardown in
legacy mode. Remove the scalable mode check in it to avoid dead code.

Remove an unnecessary check in the code as well.

Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Link: https://lore.kernel.org/r/20240305013305.204605-6-baolu.lu@linux.intel.com


Signed-off-by: Joerg Roedel <jroedel@suse.de>