st-hal: Fix deadlock for SSR during buffering

There is a deadlock that can occur when an SSR offline event
comes during buffering. The buffering thread sends a
deferred stop event to the state machine if it stops with
an error. This is intended for buffer overflow and other
possible internal errors, but not for SSR usecases.

Change-Id: I0fbba51f698784ac2f36f2526b78549b48f6f227
1 file changed