arm64/dma-mapping: Fix sizes in __iommu_{alloc,free}_attrs

arm64/dma-mapping: Fix sizes in __iommu_{alloc,free}_attrs

The iommu-dma layer does its own size-alignment for coherent DMA
allocations based on IOMMU page sizes, but we still need to consider
CPU page sizes for the cases where a non-cacheable CPU mapping is
created. Whilst everything on the alloc/map path seems to implicitly
align things enough to make it work, some functions used by the
corresponding unmap/free path do not, which leads to problems freeing
odd-sized allocations. Either way it's something we really should be
handling explicitly, so do that to make both paths suitably robust.

Reported-by: Yong Wu <yong.wu@mediatek.com>
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>