btm_sco_hfp_hal_linux: Refactor MGMT command to provide only driver info

The MGMT_OP_GET_SCO_CODEC_CAPABILITIES command actually relies on some
codec info that's cached in kernel space, while the info is considered
as memory leak and removed by https://crrev.com/c/4918531.

The kernel side patch https://crrev.com/c/5215291 refactors the MGMT
command to provide only the info that can't be queried by HCI commands
(i.e., driver info). In this patch, query codec info through
GD Controller and mimic the original MGMT command behavior.

Bug: 316077719
Tag: #floss
Test: mmm packages/modules/Bluetooth
Test: Manual test on Corsola, WBS headset works
Test: bluetooth_AdapterAUHealth.au_hfp_wbs_dut_as_source_test.floss
Flag: EXEMPT floss only changes
Change-Id: If3f07b4aa6f2a7b9709aa3ad5b845fa59b17e75b