V4L/DVB (9587): Handle changes to endpoint layout in em2874

Empia moved around their endpoint configuration in newer chips, so accommodate
the changes

Thanks for Ray Lu from Empia for providing the em2874 datasheet.

Signed-off-by: Devin Heitmueller <devin.heitmueller@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>