dt-bindings: leds: qcom-lpg: Document PM8937 PWM compatible

The PM8937 PWM modules are compatible with the PM8916 PWM modules,
document the PM8937 PWM compatible as fallback for the PM8916 PWM.

Signed-off-by: Barnabás Czémán <barnabas.czeman@mainlining.org>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20250213-pm8937-pwm-v2-1-49ea59801a33@mainlining.org


Signed-off-by: Lee Jones <lee@kernel.org>