[media] s2255drv: fix for return code not checked

Start acquisition return code was not being checked.  Return error
if start acquisition fails.

Signed-off-by: Dean Anderson <linux-dev@sensoray.com>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>