TS 33.128 CR0412 - notes for pTCCCPDU vs nIDDCCPDU

The CCPDU tag numbers for pTCCCPDU differ between Rel-16 and Rel-17:
- In Rel-16:
        pTCCCPDU            [4] PTCCCPDU
- In Rel-17 and newer:
        nIDDCCPDU           [4] NIDDCCPDU
        pTCCCPDU            [5] PTCCCPDU

Both types are OCTET STRING so a Rel-17 decoder should be able to
decode a Rel-16 CCPDU. However, the meaning of the field differs.

Add comment note to Rel-16 to not reuse CCPDU tag 5.