V4L/DVB (5012a): Remove some unused code from kernel mainstream

There are some long time unused code under some media driver source files. 
There's no need of keeping it at mainstream.
Those unused code will remain available at V4L/DVB master tree and also at
kernel history.

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