dma-pool: fix coherent pool allocations for IOMMU mappings

dma-pool: fix coherent pool allocations for IOMMU mappings

[ Upstream commit 9420139f516d7fbc248ce17f35275cb005ed98ea ]

When allocating coherent pool memory for an IOMMU mapping we don't care
about the DMA mask.  Move the guess for the initial GFP mask into the
dma_direct_alloc_pages and pass dma_coherent_ok as a function pointer
argument so that it doesn't get applied to the IOMMU case.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Tested-by: Amit Pundir <amit.pundir@linaro.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>