docs: block: blk-mq.rst: correct places -> place

Corrected a typo in the blk-mq.rst documentation where 'places' was
incorrectly used instead of 'place'.

Signed-off-by: Kuan-Wei Chiu <visitorckw@gmail.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Message-ID: <20230902164121.2653109-1-visitorckw@gmail.com>

Documentation/block/blk-mq.rst

@@ -56,7 +56,7 @@ sent to the software queue.
 Then, after the requests are processed by software queues, they will be placed
 at the hardware queue, a second stage queue where the hardware has direct access
 to process those requests. However, if the hardware does not have enough
-resources to accept more requests, blk-mq will places requests on a temporary
+resources to accept more requests, blk-mq will place requests on a temporary
 queue, to be sent in the future, when the hardware is able.
 
 Software staging queues