[PATCH 0/3] allow setting BW for R820T tunners

This is rework of previous post of patches for setting BW on R820T tunners. It contains only minor cleantups (fix grammar) and add function for getting BW. The one question remains whatever to keep or not BW setting support for really narrow bandwidth values. They does have a bit blurry edges and for unexperienced users can cause a bit of troubles in other hand for someone who knows what to do can be still usefull. P