Reland BluetoothAudio HAL: flip to be enabled by default

Check property to know whether BluetoothAudio is disabled or not, and
use old bthost_ipc when disabled.

Bug: 126304229
Test: Switch BluetoothAudio HAL and A2DP offload manully
(cherry picked from commit 409f07c01620b69aed09b993273242b37642d1e0)

Change-Id: I96dcd64ff26a4d95dc55389f6db16c12d32b3280
(cherry picked from commit 7451e9b8a1d9876b94c067743af29eea238b0ae8)
diff --git a/hal/audio_extn/a2dp.c b/hal/audio_extn/a2dp.c
index 43b3da9..6ebbfc6 100644
--- a/hal/audio_extn/a2dp.c
+++ b/hal/audio_extn/a2dp.c
@@ -79,7 +79,7 @@
 // System properties used for A2DP Offload
 #define SYSPROP_A2DP_OFFLOAD_SUPPORTED "ro.bluetooth.a2dp_offload.supported"
 #define SYSPROP_A2DP_OFFLOAD_DISABLED  "persist.bluetooth.a2dp_offload.disabled"
-#define SYSPROP_BLUETOOTH_AUDIO_HAL_ENABLED  "persist.vendor.bluetooth.bluetooth_audio_hal.enabled"
+#define SYSPROP_BLUETOOTH_AUDIO_HAL_DISABLED  "persist.vendor.bluetooth.bluetooth_audio_hal.disabled"
 #define SYSPROP_A2DP_CODEC_LATENCIES   "vendor.audio.a2dp.codec.latency"
 
 // Default encoder bit width
@@ -680,7 +680,7 @@
     int ret = 0;
     ALOGD("%s: Open A2DP output start", __func__);
     bool hal_v2_enabled =
-              property_get_bool(SYSPROP_BLUETOOTH_AUDIO_HAL_ENABLED, false);
+              !property_get_bool(SYSPROP_BLUETOOTH_AUDIO_HAL_DISABLED, false);
 
     if (a2dp.bt_state != A2DP_STATE_DISCONNECTED) {
         ALOGD("%s: Called A2DP open with improper state, Ignoring request state %d",