README: Change the tv-out example to a mode which actually exists

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
TODO: update

And move some of the notes to hansg-boards-info

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
README: Document new kernel cmdline options for tv-out

Signed-off-by: Hans de Goede <hdegoede@redhat.com>