GKI cleanup - Eliminate usage of pool buffers

* Replace usage of function GKI_getpoolbuf() with GKI_getbuf()
* Remove usage of function GKI_poolutilization()
* Remove usage of function GKI_poolfreecount()

Change-Id: Ide938192b878bbfb4912642c903fce548f2b5368
33 files changed