pulse: compute latency correctly if negative (fixes #15046)
pulse: compute latency correctly if negative (fixes #15046)

This occurs in case of large buffer underflow, such as if stopping the
VLC process.

xkfz007/vlc,xkfz007/vlc,xkfz007/vlc,xkfz007/vlc,xkfz007/vlc,xkfz007/vlc,xkfz007/vlc