Telephony: fix tdsdma asu invalid value

The magic value for invalid asu is "99", not "255". This error is causing the value validity checks to fail incorrectly, fixit.

Change-Id: Ief816eb577ccf371b3c85df1fe9515eb0bfb3f06
Merge pull request #13 from CyanogenMod/cm-11.0

Telephony: fix tdsdma asu invalid value