cxgb4: Fix {vxlan/geneve}_port initialization

adapter->rawf_cnt was not initialized, thereby
ndo_udp_tunnel_{add/del} was returning immediately
without initializing {vxlan/geneve}_port.
Also initializes mps_encap_entry refcnt.

Fixes: 846eac3f ("cxgb4: implement udp tunnel callbacks")
Signed-off-by: Arjun Vynipadath <arjun@chelsio.com>
Signed-off-by: Ganesh Goudar <ganeshgr@chelsio.com>
Signed-off-by: David S. Miller <davem@davemloft.net>