[media] media: bcm2048: remove unused return of function

Integer return of bcm2048_parse_rds_rt () is never used, changing the return
type to void.

Signed-off-by: Luis de Bethencourt <luis.bg@samsung.com>
Acked-by: Pali Rohár <pali.rohar@gmail.com>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>