docs: firmware-guide: ACPI: Add a PWM example

When PWM support for ACPI has been added into the kernel, it missed
the documentation update. Hence update documentation here.

Fixes: 4a6ef8e37c ("pwm: Add support referencing PWMs from ACPI")
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
This commit is contained in:
Andy Shevchenko 2021-06-07 15:24:53 +03:00 • committed by Thierry Reding
commit ef3d13b867