missing inline keyword for static function in linux/dmaengine.h

Add a missing inline keyword for static function in linux/dmaengine.h to
avoid duplicate symbol definitions.
Signed-off-by: Mathieu Lacage <mathieu.lacage@sophia.inria.fr>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

include/linux/dmaengine.h

@@ -548,7 +548,7 @@ static inline bool dma_dev_has_pq_continue(struct dma_device *dma)
 	return (dma->max_pq & DMA_HAS_PQ_CONTINUE) == DMA_HAS_PQ_CONTINUE;
 }
 
-static unsigned short dma_dev_to_maxpq(struct dma_device *dma)
+static inline unsigned short dma_dev_to_maxpq(struct dma_device *dma)
 {
 	return dma->max_pq & ~DMA_HAS_PQ_CONTINUE;
 }