linux-phytec-fsl

Input: imx_keypad - adapt the new kpp clock name

With the new i.mx clock framework we should pass NULL as the keypad
clock name.

Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>