linuxdvb: old code would update tuning params even without auto-discovery

This is important for correcting mistakes in the pre-defined configuration
files, and also picking up potential changes (not sure that will quite work).

The one thing that is left untouched is the frequency, a) to not confuse people
and b) I've seen 2 transponders sending slightly diff freq and this can cause
the config to be constantly updated.

The one thing this will also do, for better or worse, is remove an AUTO
settings. Cons are it could be less flexible an tuners may automatically deal
with small changes in settings, Pro's are if you have some tuners that accept
AUTO and some that don't, once its scanned on something that does it will get
updated. Plus its probably better, where possible, to have the full settings.
linuxdvb: fix some mistake in previous commits and reduce level of config saving

There was excessive saving as a result of some mistakes in the MPEGTS/DVB code.