tracing: Update tracing branch url

ftrace and perf events now use the same development branch.
Don't show a stale branch to developers.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Ingo Molnar <mingo@redhat.com>

MAINTAINERS

@@ -5644,7 +5644,7 @@ TRACING
 M:	Steven Rostedt <rostedt@goodmis.org>
 M:	Frederic Weisbecker <fweisbec@gmail.com>
 M:	Ingo Molnar <mingo@redhat.com>
-T:	git git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip.git tracing/core
+T:	git git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip.git perf/core
 S:	Maintained
 F:	Documentation/trace/ftrace.txt
 F:	arch/*/*/*/ftrace.h