hal: Fix for device check against wrong codec backend

 Make sure out stream device is checked against out codec backend
 device and in stream device against in codec backend. Checking out
 device against in codec backend or vice versa leads to issues as
 some out and in device ids are common except the bit in.

 CRs-Fixed: 1088820

Change-Id: I1197411c287cf65d41ed1d16f300e962b677b832
diff --git a/hal/msm8916/platform.h b/hal/msm8916/platform.h
index a0ae7d0..24c793e 100644
--- a/hal/msm8916/platform.h
+++ b/hal/msm8916/platform.h
@@ -240,6 +240,7 @@
     SLIMBUS_0_TX,
     DEFAULT_CODEC_TX_BACKEND = SLIMBUS_0_TX,
     USB_AUDIO_TX_BACKEND,
+    BT_SCO_TX_BACKEND,
     MAX_CODEC_BACKENDS
 };