Conditional compilation for 48KHz sample rate

PS2:
https://github.com/CyanogenMod/android_external_bluetooth_bluedroid/commit/2cbe5233895e03255d655044897b9a27fcfc4e51
All QC devices using the CodeAurora drivers should be using a 48KHz
samplerate for A2DP.

Change-Id: I0a439973605369509efd06486181007978627414