iommu/amd: Use try_cmpxchg64() in v2_alloc_pte()

iommu/amd: Use try_cmpxchg64() in v2_alloc_pte()

Use try_cmpxchg64() instead of cmpxchg64 (*ptr, old, new) != old in
v2_alloc_pte().  cmpxchg returns success in ZF flag, so this change
saves a compare after cmpxchg (and related move instruction
in front of cmpxchg).

This is the same improvement as implemented for alloc_pte() in:

  commit 0d10fe759117 ("iommu/amd: Use try_cmpxchg64 in alloc_pte and free_clear_pte")

Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
Cc: Will Deacon <will@kernel.org>
Cc: Robin Murphy <robin.murphy@arm.com>
Reviewed-by: Vasant Hegde <vasant.hegde@amd.com>
Link: https://lore.kernel.org/r/20240522082729.971123-1-ubizjak@gmail.com
Signed-off-by: Joerg Roedel <jroedel@suse.de>