Check for adpf cpu hints for SurfaceFlinger during init

Currently adpf hints for SurfaceFlinger only checks when boot finishes,
but now that it can be enabled via sysprop it's also necessary to check
during SF initialization. This patch lets SurfaceFlinger start the
session during init, and then if it becomes enabled later it will start
the session after boot instead.

Bug: b/239477143
Bug: b/195990840

Test: manual
Change-Id: Ifdbe177ab4097277a3f238653723c153f29e5b99