clk: versatile: Add device tree probing for IM-PD1 clocks

As we want to move these clocks over to probe from the device
tree we add a device tree probing path.

The old platform data path will be deleted once we have the
device tree overall code in place.

Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lkml.kernel.org/r/20200219103326.81120-3-linus.walleij@linaro.org
Signed-off-by: Stephen Boyd <sboyd@kernel.org>