[media] stb0899: use sign_extend32() for sign extension
[media] stb0899: use sign_extend32() for sign extension

Instead of implement its own logic, use the already-defined one.

Signed-off-by: Martin Kepplinger <07ddf30bcca2a0d3056e54ffbfe155352a6af244@posteo.de>
Signed-off-by: Mauro Carvalho Chehab <ad86ba2154032c9f55743a190faa2459a9d61d42@osg.samsung.com>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs