[media] bt8xx: just return 0 instead of using a var

Instead of allocating a var to store 0 and just return it,
change the code to return 0 directly.

Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>

diff --cc drivers/media/pci/bt8xx/bttv-driver.c
Simple merge

diff --cc drivers/media/pci/bt8xx/dst_ca.c
Simple merge