TS demux: fix DVB program selection
TS demux: fix DVB program selection

If the first program of the PAT has no PMT or no ES, we will get stuck forever.
Return from demux probe immediately, to let user select the desired program later.

For example on Astra S19.2E:
dvb:// --dvb-frequency 12551500 --dvb-polarization V --dvb-srate 22000000 --dvb-fec 5/6

vlc-mirror/vlc,xkfz007/vlc,krichter722/vlc,krichter722/vlc,vlc-mirror/vlc,xkfz007/vlc,vlc-mirror/vlc,xkfz007/vlc,krichter722/vlc,shyamalschandra/vlc,vlc-mirror/vlc,krichter722/vlc,vlc-mirror/vlc,shyamalschandra/vlc,krichter722/vlc,shyamalschandra/vlc,shyamalschandra/vlc,xkfz007/vlc,vlc-mirror/vlc,shyamalschandra/vlc,xkfz007/vlc,xkfz007/vlc,krichter722/vlc,shyamalschandra/vlc,vlc-mirror/vlc,shyamalschandra/vlc,krichter722/vlc,xkfz007/vlc