V4L/DVB (3406): Added credits for em28xx-video.c

- Added credits for sn9c102 kernel module and his author as
some parts of em28xx-video were based.

Acked-by: Luca Risolia <luca.risolia@studio.unibo.it>
Acked-by: Markus Rechberger <mrechberger@gmail.com>
Acked-by: Ludovico Cavedon <cavedon@sssup.it>
Acked-by: Sascha Sommer <saschasommer@freenet.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>