dma-remap: drop nth_page() in dma_common_contiguous_remap()

dma-remap: drop nth_page() in dma_common_contiguous_remap()

dma_common_contiguous_remap() is used to remap an "allocated contiguous
region".  Within a single allocation, there is no need to use nth_page()
anymore.

Neither the buddy, nor hugetlb, nor CMA will hand out problematic page
ranges.

Link: https://lkml.kernel.org/r/20250901150359.867252-24-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Acked-by: Marek Szyprowski <m.szyprowski@samsung.com>
Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>