selftests: mptcp: diag: remove trailing whitespace

It doesn't need to be there, and it can cause some issues with TAP
parsers expecting only one space around the directive delimiter (#).
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Link: https://patch.msgid.link/20240906-net-next-mptcp-ksft-subtest-time-v2-4-31d5ee4f3bdf@kernel.orgSigned-off-by: Jakub Kicinski <kuba@kernel.org>

tools/testing/selftests/net/mptcp/diag.sh

@@ -284,7 +284,7 @@ echo "b" | \
 			./mptcp_connect -p 10000 -r 0 -t ${timeout_poll} -w 20 \
 				127.0.0.1 >/dev/null &
 wait_connected $ns 10000
-chk_msk_nr 2 "after MPC handshake "
+chk_msk_nr 2 "after MPC handshake"
 chk_last_time_info 10000
 chk_msk_remote_key_nr 2 "....chk remote_key"
 chk_msk_fallback_nr 0 "....chk no fallback"