shared/vcp: Fix issues of audio location and descriptor

shared/vcp: Fix issues of audio location and descriptor

Issues
- Audio output descriptor & location read functions requires code
correction.
- During reading audio location descriptor value was checked
instead of the pointer. DBG statement wrongly accessed value
to print the log that caused the crash.

Fix
- Corrected audio output descriptor read variable
- Corrected the audio location debug printing function
- Allocated the memory as a char pointer to the audio descriptor variable.
- Corrected the audio descriptor pointer checking condition