drm/msm/hdmi: make hdmi_phy_8996 OF clk provider

On MSM8996 the HDMI PHY provides the PLL clock to the MMCC. As we are
preparing to convert the MSM8996 to use DT clocks properties (rather
than global clock names), register the OF clock provider.

While we are at it, also change the driver to use clk_parent_data rather
parent_names to setup a link to the XO clock.

Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Reviewed-by: Abhinav Kumar <quic_abhinavk@quicinc.com>
Patchwork: https://patchwork.freedesktop.org/patch/492318/
Link: https://lore.kernel.org/r/20220704161148.814510-3-dmitry.baryshkov@linaro.org
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Signed-off-by: Rob Clark <robdclark@chromium.org>