staging: android: logger: reorder prepare_to_wait and mutex_lock

If mutex_lock waits, it will return in state TASK_RUNNING,
rubbing out the effect of prepare_to_wait().

Signed-off-by: Tim Bird <tim.bird@am.sony.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>