[media] airspy: remove v4l2-compliance workaround

v4l2-compliance is now happy with frequency ranges where both lower
and upper limit is same.

Cc: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Antti Palosaari <crope@iki.fi>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>