[media] v4l2-dv-timings.h: add 480i59.94 and 576i50 CEA-861-E timings

These formats are supported by the HDPVR, but they were missing in the list.
Note that these formats are different from the common PAL/NTSC/SECAM formats
since all color channels are transmitted separately and so there is no PAL
or NTSC or SECAM color encoding involved.

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>