iommu/amd: Lock DTE before updating the entry with WRITE_ONCE()

When updating only within a 64-bit tuple of a DTE, just lock the DTE and
use WRITE_ONCE() because it is writing to memory read back by HW.

Suggested-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
Link: https://lore.kernel.org/r/20241118054937.5203-9-suravee.suthikulpanit@amd.com


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