libaudiohal: Remove DeviceHalAidl::mFwkHandles

The framework stores HAL patch handles separately
from globally unique patch handles that is generates.
There is no need for the HAL adaptor to maintain
this mapping, since it always receives HAL-specific
patch handles from the framework.

Bug: 269551518
Test: atest audiorecord_tests
Change-Id: I0bf42791126c81b4fbebd09329183e8021649df1