hwc: Register hwc3 hotplug and HDCP callbacks

The new onHotplug event and onHDCPLevelsChanged HAL APIs have been
added recently, but currently we are still using legacy onVsync hack
code paths. This CL will activate usage of the new HAL APIs by Pixel HWC

Bug: 308867147
Test: tested that external display is working with this change
Change-Id: I8729660dff6b8d2e0672bd0b5a1c15102d59d2df
1 file changed