Support blocking screen on multi-display.

- register UXR listener for each physical display;
- non-physical (likely virtual) displays gets UXR for main display;
- if no display has physical address, assume main display is physical;

Bug: 128456985
Test: verified on device with single display; also verified with
multi-display as 2nd home.
Change-Id: I54b45915e1e32f01613d3477c10b2e8c38e4e94e
4 files changed