arm-nommu: call dma_mmap_from_dev_coherent directly

There is no need to go through dma_common_mmap for the arm-nommu
dma mmap implementation as the only possible memory not handled above
could be that from the per-device coherent pool.
Signed-off-by: NChristoph Hellwig <hch@lst.de>

arch/arm/mm/dma-mapping-nommu.c

@@ -68,8 +68,9 @@ static int arm_nommu_dma_mmap(struct device *dev, struct vm_area_struct *vma,
 
 	if (dma_mmap_from_global_coherent(vma, cpu_addr, size, &ret))
 		return ret;
-
-	return dma_common_mmap(dev, vma, cpu_addr, dma_addr, size, attrs);
+	if (dma_mmap_from_dev_coherent(dev, vma, cpu_addr, size, &ret))
+		return ret;
+	return -ENXIO;
 }