Clean up post in WM package

As ATMS is now in wm package and holding the same lock, we don't need to
post the call with the WM lock any more. Messages posted to ATM Internal
from WM package is no longer needed in most cases, make a direct call
insteald.

Test: go/wm-smoke
Bug: 122825247
Change-Id: I8dba78f8b3c1bbdec452f94f1a6ffe375ba8d42e