telephony : Support for voicemail in TP-UDH of SMS

Added support for processing special message indication
for voice mail in TP user data header for SMS
Spec reference: 3GPP TS 23.040 V6.8.1

CPHS method does not use message count.
0xff is used to indicate unknown message count for CPHS
Ref[Adapt requirement CDR-MWI-120, TC: GSM-BTR-1-4700]

bug: 17299884
Change-Id: I893252d5cacd5c1c8680a8ca6c3a6dba95ef3e1f