Input: nomadik-ske-keypad - start using the apb_pclk

Previously this clock was handled internally by the clockdriver,
but now this is separate clk. So we need take care of it.

Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>