iommu/amd: Use BIT/BIT_ULL macro to define bit fields

Make use of BIT macro when defining bitfields which makes it easy to read.

No functional change intended.

Suggested-by: Yazen Ghannam <yazen.ghannam@amd.com>
Signed-off-by: Vasant Hegde <vasant.hegde@amd.com>
Link: https://lore.kernel.org/r/20230609090631.6052-1-vasant.hegde@amd.com


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