[media] vivid: Enable 4k resolution for webcam capture device

Add 3840x2160 as valid resolution for the webcam capture input and
adjust the webcam intervals accordingly.

Signed-off-by: Soren Brinkmann <soren.brinkmann@xilinx.com>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>