[PATCH] DMA-mapping.txt typo fix

Roger Luethi <rl@hellgate.ch>: DMA-mapping.txt: sg_dma_length() -> sg_dma_len():

Documentation/DMA-mapping.txt

@@ -484,7 +484,7 @@ limited number of scatter-gather entries) and returns the actual number
 of sg entries it mapped them to.
 
 Then you should loop count times (note: this can be less than nents times)
-and use sg_dma_address() and sg_dma_length() macros where you previously
+and use sg_dma_address() and sg_dma_len() macros where you previously
 accessed sg->address and sg->length as shown above.
 
 To unmap a scatterlist, just call: