qcacmn: Register API to flush frags in dp peer ops

Register dp_peer_flush_frags API in dp peer ops
for flushing fragments for a particular peer.

Change-Id: Ia179d3160bdc306ec965c465134042c66a0c40a6
CRs-Fixed: 2874366

dp/wifi3.0/dp_main.c

@@ -12639,6 +12639,7 @@ static struct cdp_peer_ops dp_ops_peer = {
 	.get_vdev_by_peer_addr = dp_get_vdev_by_peer_addr,
 	.peer_get_peer_mac_addr = dp_peer_get_peer_mac_addr,
 	.get_peer_state = dp_get_peer_state,
+	.peer_flush_frags = dp_peer_flush_frags,
 };
 #endif