media: vidioc-cropcap/g-crop.rst: fix confusing sentence

The note that the text refers to is actually *below* the type description,
not above.

Fix this.

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>