dt-bindings: clock: renesas,cpg-clocks: Document ZT/ZTR trace clock on R-Mobile APE6

dt-bindings: clock: renesas,cpg-clocks: Document ZT/ZTR trace clock on R-Mobile APE6

Document the ZT trace bus and ZTR trace clocks on R-Mobile APE6.  These
clocks supply the coresight tracing modules, PTM, TPIU, ETB and
replicator.  Without these clocks, coresight tracing can not be
operated.  While this does change the ABI, it does so by extending the
existing clock-output-names, therefore if old software is used with new
DT, the coresight tracing parts will likely fail to probe, otherwise if
new software is used with an old DT, there is no impact.

Signed-off-by: Marek Vasut <marek.vasut+renesas@mailbox.org>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://patch.msgid.link/20260502185557.93061-2-marek.vasut+renesas@mailbox.org
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>