[media] V4L: videobuf, don't use dma addr as physical

mem->dma_handle is a dma address obtained by dma_alloc_coherent which
needn't be a physical address in presence of IOMMU, as
a hardware IOMMU can (and most likely) will return a bus address where
physical != bus address.

So ensure we are remapping (remap_pfn_range) the right page in
__videobuf_mmap_mapper by using virt_to_phys(mem->vaddr) and not
mem->dma_handle.

While at it, use PFN_DOWN instead of explicit shift.

[mchehab@redhat.com: Fix compilation breakage due to the lack of a comma]
Signed-off-by: NJiri Slaby <jslaby@suse.cz>
Reviewed-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: NMauro Carvalho Chehab <mchehab@redhat.com>

drivers/media/video/videobuf-dma-contig.c

@@ -300,7 +300,7 @@ static int __videobuf_mmap_mapper(struct videobuf_queue *q,
 
 	vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
 	retval = remap_pfn_range(vma, vma->vm_start,
-				 mem->dma_handle >> PAGE_SHIFT,
+				 PFN_DOWN(virt_to_phys(mem->vaddr)),
 				 size, vma->vm_page_prot);
 	if (retval) {
 		dev_err(q->dev, "mmap: remap failed with error %d. ", retval);