[media] V4L: Remove deprecated image centering controls

It has been over 3 years since the V4L2_CID_[HV]CENTER were deprecated.
Clean up the DocBook and remove the V4L2_CID_VCENTER_DEPRECATED,
V4L2_CID_VCENTER_DEPRECATED control related paragraphs.
Remove the V4L2_CID_[HV]CENTER controls definitions from v4l2-controls.h,
these controls are not used by any driver in the mainline now.

Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>