V4L/DVB (3336): Bt8xx documentation authors fix

- use one Author per line, which allows us to add more
  authors later without creating a mess.
- Add Michael Krufky due to -git commit
	2cbeddc976645262dbe036d6ec0825f96af70da3

Signed-off-by: Michael Krufky <mkrufky@linuxtv.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>