patch for bktr(4): better luma notch filter ioctls

[Julian Elischer]

Jacob Meuser wrote:
> the current luma notch interface does not jive with the datasheet,
> and it really doesn't seem to work as expected. instead of changing
> the bahaviour of the current ioctls and potentially breaking
> programs, add new ioctls.
> 


so we need some people with brooktree cards to confirm these patches work
if they do, then we can commit them..