clk: qcom: apcs-msm8916: use clk_parent_data to specify the parent

Allow accessing the parent clock names required for the driver
operation by using the device tree node, while falling back to
the previous method of using names in the global name space.

This permits extending the driver to other platforms without having to
modify its source code.

Co-developed-by: Jorge Ramirez-Ortiz <jorge.ramirez-ortiz@linaro.org>
Signed-off-by: Jorge Ramirez-Ortiz <jorge.ramirez-ortiz@linaro.org>
Signed-off-by: Niklas Cassel <niklas.cassel@linaro.org>