dma-mapping: add unlikely hint to error path in dma_mapping_error

Zillions of drivers use the unlikely() hint when checking the result of
dma_mapping_error(). This is an inline function anyway, so we can move
the hint into the function and remove it from drivers over time.

Signed-off-by: Heiner Kallweit <[e-mail]>
Reviewed-by: Robin Murphy <[e-mail]>
Signed-off-by: Christoph Hellwig <[e-mail]>

include/linux/dma-mapping.h

···
 {
 	debug_dma_mapping_error(dev, dma_addr);
 
-	if (dma_addr == DMA_MAPPING_ERROR)
+	if (unlikely(dma_addr == DMA_MAPPING_ERROR))
 		return -ENOMEM;
 	return 0;
 }