perf: add libtraceevent packageconfig

With kernel 6.4-rc1 commit 6898e60f709b ("perf build: If libtraceevent
isn't present error the build") having libtraceevent is a required
dependency unless building it with 'NO_LIBTRACEEVENT=1'.

Older kernels did build libtraceevent as provided by the kernel sources.
(Unless LIBTRACEEVENT_DYNAMIC=1 was defined, then it tried to pickup
an external provided libtraceevent and printed a warning if not found.)

Add a libtraceevent packageconfig which adds the dependency on
libtraceevent if set, otherwise builds with NO_LIBTRACEEVENT=1.
For older kernels the old behaviour of building libtraceevent from
the kernel sources isn't changed.

Signed-off-by: Max Krummenacher <max.krummenacher@toradex.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>