Add user control to adjust generated FM deviation.
Default it to 75kHz like public FM radio broadcast.
Signed-off-by: NAntti Palosaari <crope@iki.fi>
Signed-off-by: NHans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: NMauro Carvalho Chehab <mchehab@osg.samsung.com>