block: remove extern on function definition

Intoduced between 2.6.25-rc2 and -rc3
block/blk-settings.c:319:12: warning: function 'blk_queue_dma_drain' with external linkage has definition

Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

block/blk-settings.c

@@ -332,7 +332,7 @@ EXPORT_SYMBOL(blk_queue_dma_pad);
  * device can support otherwise there won't be room for the drain
  * buffer.
  */
-extern int blk_queue_dma_drain(struct request_queue *q,
+int blk_queue_dma_drain(struct request_queue *q,
 			       dma_drain_needed_fn *dma_drain_needed,
 			       void *buf, unsigned int size)
 {