net: openvswitch: add misc error drop reasons

Use drop reasons from include/net/dropreason-core.h when a reasonable
candidate exists.

Acked-by: Aaron Conole <aconole@redhat.com>
Signed-off-by: Adrian Moreno <amorenoz@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>