[media] vb2: Fix dma_dir setting for dma-contig mem type

The last argument of vb2_dc_get_user_pages() is of type enum
dma_data_direction, but the caller, vb2_dc_get_userptr() passes a value
which is the result of comparison dma_dir == DMA_FROM_DEVICE. This results
in the write parameter to get_user_pages() being zero in all cases, i.e.
that the caller has no intent to write there.

This was broken by patch "vb2: replace 'write' by 'dma_dir'".
Signed-off-by: NSakari Ailus <sakari.ailus@linux.intel.com>
Cc: stable@vger.kernel.org  # for v3.19
Acked-by: NHans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: NMauro Carvalho Chehab <mchehab@osg.samsung.com>

drivers/media/v4l2-core/videobuf2-dma-contig.c

@@ -632,8 +632,7 @@ static void *vb2_dc_get_userptr(void *alloc_ctx, unsigned long vaddr,
 	}
 
 	/* extract page list from userspace mapping */
-	ret = vb2_dc_get_user_pages(start, pages, n_pages, vma,
-				    dma_dir == DMA_FROM_DEVICE);
+	ret = vb2_dc_get_user_pages(start, pages, n_pages, vma, dma_dir);
 	if (ret) {
 		unsigned long pfn;
 		if (vb2_dc_get_user_pfn(start, n_pages, vma, &pfn) == 0) {