MAINTAINERS: add scripts/tracing/ to TRACING

The files in scripts/tracing/ belong to the TRACING subsystem.

Add a corresponding file entry for TRACING.

Link: https://lkml.kernel.org/r/20220825115927.20598-1-lukas.bulwahn@gmail.com

Signed-off-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>