protocol-native: Stop auto timing updates if connected to suspended sink or source

protocol-native: Stop auto timing updates if connected to suspended sink or source

This quite is an old patch. It was added to N900 to avoid unnecessary
wake-ups when the phone is in power save mode (= blank screen and
no user interaction). In this situation if the user had a browser
window with flash animation open pulseaudio kept waking up every
10 seconds, causing a severe hit to use times.

Anyway I do not see any reason to send timing updates if the sink or
source where the stream is connected to is suspended.