drm/msm/hdmi: Convert PHY files according to new design

Remove the old PHY ops managed by hdmi_platform_config and use them as ops
provided by the HDMI PHY driver.

Remove the old HDMI 8960 PLL code that used the top level HDMI TX mmio
base.

NOTE: With this commit, HDMI functionality will break until the HDMI
PHY/PLL register offsets in hdmi.xml.h aren't updated to be used as
separate domains.

Signed-off-by: Archit Taneja <architt@codeaurora.org>
Signed-off-by: Rob Clark <robdclark@gmail.com>