V4L/DVB (3408): Included new sliced VBI types to videodev2.h and tvp5150

- Added other sliced VBI types to videodev2.h
- tvp5150 now uses standard V4L2 API codes from videodev2.h
- Implemented VIDIOC_G_SLICED_VBI_CAP for tvp5150. This is
dynamically filled based on defined VDP C-RAM values filled
by the driver.

Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>