Fix Channel Tuning Broken with DVB-C (Ziggo), closes #7486

[bas-t]

Credits Christian Güdel, Dibblah and Klaas de Waal

This saves us a lot of headache in The Netherlands, possibly elswhere too.

[dekarl]

Is that mythtv_fix_broken_providers_with_gui.3.diff from #7486 applied to master? No point in wasting developer time by looking at the same patch three times :-)
Just adding "I have been running with that patch for N month, it solved the issue for me. I was not able to scan channels without it" to the ticket should be all it takes.

[bas-t]

It is indeed the mythtv_fix_broken_providers_with_gui.3.diff from #7486 applied to master, as well as fixes/0.25.
The 'N month' part of your comment does not apply. The patch is only active during scanning. I scanned 7 times, just to make sure it does solve the issue for me. It does very much so!
Ziggo, my provider, has changed some channels lately, so I had the chance to scan once more. It still solved my issue.

[bas-t]

This PR is a dupe, so not needed.