iommu/pages: Remove __iommu_alloc_pages()/__iommu_free_pages()

These were only used by tegra-smmu and leaked the struct page out of the
API. Delete them since tega-smmu has been converted to the other APIs.

In the process flatten the call tree so we have fewer one line functions
calling other one line functions.. iommu_alloc_pages_node() is the real
allocator and everything else can just call it directly.

Reviewed-by: Lu Baolu <baolu.lu@linux.intel.com>
Reviewed-by: Mostafa Saleh <smostafa@google.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Link: https://lore.kernel.org/r/3-v4-c8663abbb606+3f7-iommu_pages_jgg@nvidia.com


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