[media] msi2500: cleanups

Rename state to dev.
Correct some indentations.
Remove FSF address.
Fix some style issues reported by checkpatch.pl.
Correct some style issues I liked.

Signed-off-by: Antti Palosaari <crope@iki.fi>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>