V4L/DVB (3100): fix compile error, remove dead code and volume scaling

- Fix compile error (missing '}') in em28xx-video.c. Remove dead code and
volume scaling from msp3400.c. Volume scaling does not belong there, it should
be done in the driver for the card that uses the msp3400 if needed, not in the
msp3400.c source. The volume scaling code gave problems with the ivtv driver
which does not need to do any scaling.

Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@brturbo.com.br>