blktrace: fix blk_rq_issue documentation

The commit 881245d ("Add DocBook documentation for the block tracepoints.")
added the comment for blk_rq_issue() tracepoint. Remove the duplicate
word from the tracepoint documentation.

Fixes: 881245d ("Add DocBook documentation for the block tracepoints.")
Signed-off-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Damien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

include/trace/events/block.h

@@ -196,7 +196,7 @@ DEFINE_EVENT(block_rq, block_rq_insert,
 
 /**
  * block_rq_issue - issue pending block IO request operation to device driver
- * @rq: block IO operation operation request
+ * @rq: block IO operation request
  *
  * Called when block operation request @rq from queue @q is sent to a
  * device driver for processing.