[media] c8sectpfe: fix return of garbage

The variable err was never initialized, that means we had been checking
a garbage value in the for loop. Moreover if the segment is not outside
the firmware file then also we have been returning the garbage.
Initialize it to 0 so that on success we return the value and no need to
check in the for loop also as it is initially 0 and whenever that value
changes we have done a break from the loop.

Signed-off-by: Sudip Mukherjee <sudip@vectorindia.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>