V4L/DVB (13834): dib8000: fix compilation if !DVB_DIB8000

As reported by Randy Dunlap <randy.dunlap@oracle.com>:
> drivers/media/dvb/frontends/dib8000.h:104: error: expected expression before '}' token
> drivers/media/dvb/frontends/dib8000.h:104: warning: left-hand operand of comma expression has no effect
>
>     return CT_SHUTDOWN,
>
> s/,/;/ and fix indentation.

Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>