[media] DocBook: fix xref to the FE open() function

Instead of going to the V4L2 open(), use the xref to the
proper place at the frontend ioctls that were already
reformatted.

Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>

diff --cc Documentation/DocBook/media/dvb/dvbproperty.xml
Simple merge

diff --cc Documentation/DocBook/media/dvb/frontend_get_info.xml
Simple merge

diff --cc Documentation/DocBook/media/dvb/frontend_read_status.xml
Simple merge

diff --cc Documentation/DocBook/media_api.tmpl
Simple merge