[submodule] advance sonic-swss submodule

Submodule src/sonic-swss 65a0256..bf21ee3:
  > On a routing vlan, the neighbor entry in the /31 subnet is not added … (sonic-net#784)
  > portsorch ports init done flag should means buffer, autoneg, speed, m… (sonic-net#747) (sonic-net#783)

Signed-off-by: Ying Xie <ying.xie@microsoft.com>