Cleanup: remove LE audio hardware offload supported by openProvider_2_1

LE audio hardware offload would be supported after the temporal bluetooth.audio@2.2 or bluetooth.audio aidl version. The workable audio configuration and capabilities format do not exist in bluetooth.audio@2.1. Remove the support in the 2.1 HAL default implementation.

Bug: 197296692
Bug: 150670922
Test: make build
Change-Id: I6ff3f6ada43474cadb026bf8b58d64adaf5ea477