As its used inside iommu.c only. Also rename function to dev_update_dte()
as its static function.

No functional changes intended.
Signed-off-by: Vasant Hegde <vasant.hegde@amd.com>
Reviewed-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
Link: https://lore.kernel.org/r/20240828111029.5429-9-vasant.hegde@amd.comSigned-off-by: Joerg Roedel <jroedel@suse.de>