Input: pwm-vibrator - correct pwms in DT binding example

In the example for the pwm-vibrator bindings, pwm8 is the direction pin,
and pwm9 is the enable pin. The pwms on the vibrator node has these two
values swapped so this patch corrects it.

Signed-off-by: Brian Masney <masneyb@onstation.org>
Reviewed-by: Sebastian Reichel <sebastian.reichel@collabora.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>