tc: Add space after format specifier

tc: Add space after format specifier

Add space after format specifier in print_string call. Fixes broken
qdisc tests within tdc testing suite. Per suggestion from Petr Machata,
remove a space and change spacing in tc/q_event.c to complete the fix.

Tested fix in tdc using:
./tdc.py -c qdisc

All qdisc RED tests return ok.

Fixes: d0e450438571("tc: q_red: Add support for qevents "mark" and "early_drop")
Signed-off-by: Briana Oursler <briana.oursler@gmail.com>
Tested-by: Petr Machata <petrm@mellanox.com>
Signed-off-by: David Ahern <dsahern@kernel.org>