ANDROID: topology: Add flag to indicate topology has been updated

Commit f7128c75 ("ANDROID: sched: Add vendor hooks for update_topology")
was intended for the modules to get informed when topology
initialization had completed.

However that is not sufficient, the module could be insmoded after
the hook was invoked.

For such situations create a flag for modules to detect that topology
initialization is completed.

Bug: 187234873
Change-Id: I2ed4dff9c921e3de67dd11049c80f38e3c1a64fd
Signed-off-by: Abhijeet Dharmapurikar <adharmap@codeaurora.org>