iommu/vt-d: Use device_domain_lock accurately

The device_domain_lock is used to protect the device tracking list of
a domain. Remove unnecessary spin_lock/unlock()'s and move the necessary
ones around the list access.

Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Link: https://lore.kernel.org/r/20220706025524.2904370-11-baolu.lu@linux.intel.com


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