[media] s2255drv: avoid a switch fall through

On this driver, it can fall through a switch. I tried to
annotate it, in order to shut up a gcc warning, but that
didn't work, as the logic there is somewhat complex.

So, instead, let's just repeat the code. gcc should likely
optimize it anyway, and this makes the code better readable,
IMHO.

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