Merge branch 'mptcp-better-validation-of-mptcpopt_mp_join-option'

Eric Dumazet says:

====================
mptcp: better validation of MPTCPOPT_MP_JOIN option

Based on a syzbot report (see 4th patch in the series).

We need to be more explicit about which one of the
following flag is set by mptcp_parse_option():

- OPTION_MPTCP_MPJ_SYN
- OPTION_MPTCP_MPJ_SYNACK
- OPTION_MPTCP_MPJ_ACK

Then select the appropriate values instead of OPTIONS_MPTCP_MPJ

Paolo suggested to do the same for OPTIONS_MPTCP_MPC (5th patch)
====================

Link: https://lore.kernel.org/r/20240111194917.4044654-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>