capmt: fix numbering services after a686fe3

The commit fixes simultaneous channel decryption.
We are enumerating services based on the generated seq value.
In fact it should be elementary stream PID, but currently
we can leave it until PMT code rework.

The CA_SET_PID and CA_SET_DESCR from OSCam was always set with
seq=0 leading to setting all keys always to first subscribed
service.