[media] v4l2-ctrls.h: Document a few missing arguments

Warning(.//include/media/v4l2-ctrls.h:217): No description found for parameter 'p_new'
Warning(.//include/media/v4l2-ctrls.h:217): No description found for parameter 'p_cur'
Warning(.//include/media/v4l2-ctrls.h:217): Excess struct/union/enum/typedef member 'val64' description in 'v4l2_ctrl'
Warning(.//include/media/v4l2-ctrls.h:314): No description found for parameter 'qmenu_int'

Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
Acked-by: Jonathan Corbet <corbet@lwn.net>