libbinder: remove SM Static.cpp vars.

No need for global exported static state anymore. This also
creates a new lock (gPermissionControllerLock) which controls
access to gPermissionController since there wasn't a reason to
have access to this and sm excluded (likely was out of convenience).

Bug: 129785390
Test: TH
Change-Id: I15bbe2f0ef4f73c555798cd7674edcc56e923575