Currently the socket level counter aggregating the received data
does not take in account the data received via fastopen.

Address the issue updating the counter as required.

Fixes: 38967f42 ("mptcp: track some aggregate data counters")
Reviewed-by: Mat Martineau <martineau@kernel.org>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Mat Martineau <martineau@kernel.org>
Link: https://lore.kernel.org/r/20231023-send-net-next-20231023-2-v1-2-9dc60939d371@kernel.orgSigned-off-by: Jakub Kicinski <kuba@kernel.org>