Input: zforce - use internal pdata pointer instead of dev_get_platdata

Devicetree support will be creating its own platfprm data structure that
is not attached to the device. Let's use the internal pointer to the
pdata instead of re-fetching it with dev_get_platdata().

Signed-off-by: Heiko Stuebner <heiko.stuebner@bqreaders.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>