Merge branch 'mptcp-track-more-fallback-cases'

Matthieu Baerts says:

====================
mptcp: track more fallback cases

This series has two patches linked to fallback to TCP:

- Patch 1: additional MIB counters for remaining error code paths around
  fallback

- Patch 2: remove dedicated pr_debug() linked to fallback now that
  everything should be covered by dedicated MIB counters.
====================

Link: https://patch.msgid.link/20250723-net-next-mptcp-track-fallbacks-v1-0-a83cce08f2d5@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>