datapath: drop unneeded BUG_ON() in ovs_flow_cmd_build_info()

datapath: drop unneeded BUG_ON() in ovs_flow_cmd_build_info()

Upstream commit:
    commit 8ffeb03fbba3b599690b361467bfd2373e8c450f
    Author: Paolo Abeni <pabeni@redhat.com>
    Date:   Sun Dec 1 18:41:24 2019 +0100

    openvswitch: drop unneeded BUG_ON() in ovs_flow_cmd_build_info()

    All the callers of ovs_flow_cmd_build_info() already deal with
    error return code correctly, so we can handle the error condition
    in a more gracefull way. Still dump a warning to preserve
    debuggability.

    v1 -> v2:
     - clarify the commit message
     - clean the skb and report the error (DaveM)

    Fixes: ccb1352e76cf ("net: Add Open vSwitch kernel components.")
    Signed-off-by: Paolo Abeni <pabeni@redhat.com>
    Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Yi-Hung Wei <yihung.wei@gmail.com>
Signed-off-by: Greg Rose <gvrose8192@gmail.com>
Signed-off-by: Ilya Maximets <i.maximets@ovn.org>