clk: qcom: hfpll: use clk_parent_data to specify the parent

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

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