rapidio: fix new kernel-doc warnings

Fix new rapidio kernel-doc warnings:

  Warning(drivers/rapidio/rio-scan.c:953): No description found for parameter 'prev'
  Warning(drivers/rapidio/rio-scan.c:953): No description found for parameter 'prev_port'
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Cc: Alexandre Bounine <alexandre.bounine@idt.com>
Cc: Matt Porter <mporter@kernel.crashing.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/rapidio/rio-scan.c

@@ -943,6 +943,8 @@ static int rio_enum_complete(struct rio_mport *port)
  * @port: Master port to send transactions
  * @destid: Current destination ID in network
  * @hopcount: Number of hops into the network
+ * @prev: previous rio_dev
+ * @prev_port: previous port number
  *
  * Recursively discovers a RIO network.  Transactions are sent via the
  * master port passed in @port.