Add support for requesting an inverted PWM pulse (active-low) when
setting up the period and pulse width of a PWM pin. This is useful
when driving external, active-low circuitry (e.g. an LED) with a PWM
signal.
All in-tree PWM drivers is updated to match the new API signature, but
no driver support for inverted PWM signals is added yet.
All in-tree PWM consumers are updated to pass a flags value of 0
(0 meaning default, which is normal PWM polarity).
Fixes#21384.
Signed-off-by: Henrik Brix Andersen <hebad@vestas.com>
db611e6781