iommu/pages: Remove iommu_alloc_page_node()

Use iommu_alloc_pages_node_sz() instead.

AMD and Intel are both using 4K pages for these structures since those
drivers only work on 4K PAGE_SIZE.

riscv is also spec'd to use SZ_4K.

Reviewed-by: Lu Baolu <baolu.lu@linux.intel.com>
Tested-by: Alejandro Jimenez <alejandro.j.jimenez@oracle.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Link: https://lore.kernel.org/r/21-v4-c8663abbb606+3f7-iommu_pages_jgg@nvidia.com


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