This adds support for an SDR capture device. It generates simple
sine/cosine waves. The code for that has been contributed by
Antti.
Signed-off-by: NAntti Palosaari <crope@iki.fi>
Signed-off-by: NHans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: NMauro Carvalho Chehab <m.chehab@samsung.com>