There are no more users of pwm-beeper driver in mainline relying on
this legacy API, so let's remove it and simplify the driver code.
Acked-by: NThierry Reding <thierry.reding@gmail.com>
Tested-by: NDavid Lechner <david@lechnology.com>
Signed-off-by: NDmitry Torokhov <dmitry.torokhov@gmail.com>