iommu/amd: Move V2 page table support check to early_amd_iommu_init()

amd_iommu_pgtable validation has to be done before calling
iommu_snp_enable(). It can be done immediately after reading IOMMU
features. Hence move this check to early_amd_iommu_init().

Signed-off-by: Vasant Hegde <vasant.hegde@amd.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Link: https://lore.kernel.org/r/20241028093810.5901-7-vasant.hegde@amd.com


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