Remove internal display related methods

Sync with changes made in SurfaceFlinger and SurfaceComposerClient.
Use the system property, persist.boot.animation.displays, to determine
the displays to show the boot animation. If the system property is not
present, the first display from the display list is used.

Bug: 241285477
Test: manual, run bootanim command to verify
Change-Id: If29ecb12a68fc075daef2b8f674995d0f11cbc09