V4L/DVB (6119): ivtvfb: renamed ivtv-fb to ivtvfb, move header to include/linux

The convention for framebuffer devices is to call them xxxfb, not xxx-fb.
Conform to this. Also move the ivtvfb.h header to include/linux: it is a
public header. The FBIO_WAITFORVSYNC ioctl is now also defined in the
ivtvfb.h header, no more need to include matroxfb.h for just this ioctl.

Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>