ss: fix fallback to procfs for raw sockets

ss: fix fallback to procfs for raw sockets

Jonas reports that ss -awp does not display any RAW sockets
on a Knoppix 4.4 kernel.

sockdiag_send() diverts to tcpdiag_send() to try the older
netlink interface. tcpdiag_send() works for TCP and DCCP
but not other protocols. Instead of rejecting unsupported
protocols (and missing RAW and SCTP) match on supported ones.

Link: https://lore.kernel.org/netdev/20210815231738.7b42bad4@mmluhan/
Reported-and-tested-by: Jonas Bechtel <post@jbechtel.de>
Fixes: 41fe6c34de50 ("ss: Add inet raw sockets information gathering via netlink diag interface")
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>