qapi: spelling fix (addtional)

Fixes: 3d0d3c3
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
Message-Id: <20210508093315.393274-1-mjt@msgid.tls.msk.ru>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

qapi/qom.json

@@ -251,8 +251,8 @@
 #
 # @max_queue_size: the maximum number of packets to keep in the queue for
 #                  comparing with incoming packets from @secondary_in.  If the
-#                  queue is full and addtional packets are received, the
-#                  addtional packets are dropped. (default: 1024)
+#                  queue is full and additional packets are received, the
+#                  additional packets are dropped. (default: 1024)
 #
 # @vnet_hdr_support: if true, vnet header support is enabled (default: false)
 #