libtraceevent: Fixed type in PRINT_FMT_STING

PRINT_FMT_STING -> PRINT_FMT_STRING

Link: https://lore.kernel.org/r/CAM9d7cj1LJ=QO8QxhBo_oDM9APpAswX4BbTwge0JhZ3Y4-Bv9w@mail.gmail.com
Link: https://lore.kernel.org/linux-trace-devel/20200714103027.2477584-7-tz.stoyanov@gmail.com
Link: https://lore.kernel.org/linux-trace-devel/20200716092014.2613403-7-tz.stoyanov@gmail.com



Suggested-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Tzvetomir Stoyanov (VMware) <tz.stoyanov@gmail.com>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: linux-trace-devel@vger.kernel.org
Link: http://lore.kernel.org/lkml/20200722011755.442308322@goodmis.org


Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>