iommu/vt-d: Remove unneeded validity check on dev

dev_iommu_priv_get() is being used at the top of this function which
dereferences dev. Dev cannot be NULL after this. Remove the validity
check on dev and simplify the code.

Signed-off-by: Muhammad Usama Anjum <usama.anjum@collabora.com>
Link: https://lore.kernel.org/r/20220313150337.593650-1-usama.anjum@collabora.com


Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Link: https://lore.kernel.org/r/20220510023407.2759143-2-baolu.lu@linux.intel.com


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