net: 9p: drop duplicate word in comment

Drop doubled word "not" in a comment.
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: netdev@vger.kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

include/net/9p/transport.h

@@ -25,7 +25,7 @@
  * @request: member function to issue a request to the transport
  * @cancel: member function to cancel a request (if it hasn't been sent)
  * @cancelled: member function to notify that a cancelled request will not
- *             not receive a reply
+ *             receive a reply
  *
  * This is the basic API for a transport module which is registered by the
  * transport module with the 9P core network module and used by the client