pwm: meson: Add generic compatible for meson8 to sm1

pwm: meson: Add generic compatible for meson8 to sm1

Introduce a new compatible support in the Amlogic PWM driver.

The PWM HW is actually the same for all SoCs supported so far. A specific
compatible is needed only because the clock sources of the PWMs are
hard-coded in the driver.

It is better to have the clock source described in DT but this changes the
bindings so a new compatible must be introduced.

When all supported platform have migrated to the new compatible, support
for the legacy ones may be removed from the driver.

The addition of this new compatible makes the old ones obsolete, as
described in the DT documentation.

Adding a callback to setup the clock will also make it easier to add
support for the new PWM HW found in a1, s4, c3 and t7 SoC families.

Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
Link: https://lore.kernel.org/r/20240221151154.26452-6-jbrunet@baylibre.com
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>