hal: Add support for speaker safe and BT A2DP usecases

Add backend configuration in audio HAL for speaker safe and
BT A2DP usecases.

Bug: 79873626
Test: play ringtone with BT A2DP headset connected
Change-Id: I2a14098a1f1d812e48dda48c4e46c4663362e7fe
diff --git a/hal/msm8974/platform.h b/hal/msm8974/platform.h
index f512de3..cc5187d 100644
--- a/hal/msm8974/platform.h
+++ b/hal/msm8974/platform.h
@@ -80,6 +80,7 @@
     SND_DEVICE_OUT_BT_SCO_WB,
     SND_DEVICE_OUT_BT_A2DP,
     SND_DEVICE_OUT_SPEAKER_AND_BT_A2DP,
+    SND_DEVICE_OUT_SPEAKER_SAFE_AND_BT_A2DP,
     SND_DEVICE_OUT_VOICE_HANDSET_TMUS,
     SND_DEVICE_OUT_VOICE_TTY_FULL_HEADPHONES,
     SND_DEVICE_OUT_VOICE_TTY_VCO_HEADPHONES,