V4L/DVB (4660): Some cleanups at helper chips menu

Rearranged itens, so that decoders came first;
cx25840 is, in fact, an audio and video decoder;
Fixed some incorrect upercases;
Removed the word "chip" for some audio processors at item name;
Removed the word "driver" for some item names;

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