dma-mapping: use dma_get_mask in dma_addressing_limited

We currently have cases where the dma_addressing_limited() gets
called with dma_mask unset. This causes a NULL pointer dereference.

Use dma_get_mask() accessor to prevent the crash.

Fixes: b8664554 ("dma-mapping: add a dma_addressing_limited helper")
Signed-off-by: Eric Auger <eric.auger@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

include/linux/dma-mapping.h

@@ -689,8 +689,8 @@ static inline int dma_coerce_mask_and_coherent(struct device *dev, u64 mask)
  */
 static inline bool dma_addressing_limited(struct device *dev)
 {
-	return min_not_zero(*dev->dma_mask, dev->bus_dma_mask) <
-		dma_get_required_mask(dev);
+	return min_not_zero(dma_get_mask(dev), dev->bus_dma_mask) <
+			    dma_get_required_mask(dev);
 }
 
 #ifdef CONFIG_ARCH_HAS_SETUP_DMA_OPS