With all of our existing users of cuda_sdk switched over to ffnvcodec,
we could remove cuda_sdk completely and say that we should no longer
add code that requires the full sdk, and rather insist that such code
only use ffnvcodec.

As discussed previously, the use of nvcc from the sdk is still
supported with a distinct option.
Signed-off-by: Philip Langdale <philipl@overt.org>
Signed-off-by: Timo Rothenpieler <timo@rothenpieler.org>