vswitchd: Update documentation for legacy_l3 type packets
The documentation needs to specify that for GRE tunnels there is no
support for legacy_l3 type packets in the kernel datapath.
Acked-by: William Tu
represented as Ethernet frames for compatibility with legacy
OpenFlow controllers that expect this behavior.
</li>
+ <li>
+ The <code>legacy_l3</code> option is only available via the
+ user space datapath. The OVS kernel datapath does not support
+ devices of type ARPHRD_IPGRE which is the requirement for
+ <code>legacy_l3</code> type packets.
+ </li>
<li>
If this option is <code>ptap</code>, the tunnel sends and
receives any kind of packet. Open vSwitch represents packets in
