IB/uverbs: Introduce egress flow steering

The egress flag indicates that this flow steering rule is for egress
traffic. The scope of an egress rule is port-wide, meaning all packets
originated from that port, which match the steering rule specification
will be effected by this steering rule's action.
Reviewed-by: Yishai Hadas <yishaih@mellanox.com>
Signed-off-by: Boris Pismenny <borisp@mellanox.com>
Reviewed-by: Matan Barak <matanb@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

include/rdma/ib_verbs.h

@@ -1854,7 +1854,8 @@ enum ib_flow_domain {
 
 enum ib_flow_flags {
 	IB_FLOW_ATTR_FLAGS_DONT_TRAP = 1UL << 1, /* Continue match, no steal */
-	IB_FLOW_ATTR_FLAGS_RESERVED  = 1UL << 2  /* Must be last */
+	IB_FLOW_ATTR_FLAGS_EGRESS = 1UL << 2, /* Egress flow */
+	IB_FLOW_ATTR_FLAGS_RESERVED  = 1UL << 3  /* Must be last */
 };
 
 struct ib_flow_eth_filter {