datapath: Drop packets when interdev is not up

If the internal device is not up, it should drop received
packets. Sometimes it receive the broadcast or multicast
packets, and the ip protocol stack will casue more cpu
usage wasted.

Signed-off-by: Chunhe Li <lichunhe@huawei.com>
Acked-by: Pravin B Shelar <pshelar@nicira.com>
datapath: Remove redundant key ref from upcall_info.

struct dp_upcall_info has pointer to pkt_key which is already
available in OVS_CB.  This also simplifies upcall handling
for gso packet.

Signed-off-by: Pravin B Shelar <pshelar@nicira.com>
Acked-by: Andy Zhou <azhou@nicira.com>