pwm: Add tracing for waveform callbacks

This adds trace events for the recently introduced waveform callbacks.
With the introduction of some helper macros consistency among the
different events is ensured.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@baylibre.com>
Link: https://lore.kernel.org/r/1d71879b0de3bf01459c7a9d0f040d43eb5ace56.1726819463.git.u.kleine-koenig@baylibre.com


Signed-off-by: Uwe Kleine-König <ukleinek@kernel.org>