tracing: Fix missing * in comment block

There is a missing * in a comment block, add it in.

Link: https://lkml.kernel.org/r/20211006172830.1025336-1-colin.king@canonical.com



Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>