hal: Fix voice call usecase de-referencing

Fix referencing of voice call use case only
when the use case is relevant

CRs-Fixed: 1017180
Change-Id: I29ebfd75c8953ff3d464bdb8d7ff7b77cf2cbdf6
diff --git a/hal/audio_hw.c b/hal/audio_hw.c
index c53f124..ad565de 100644
--- a/hal/audio_hw.c
+++ b/hal/audio_hw.c
@@ -1037,9 +1037,9 @@
         if (voice_is_in_call(adev) && adev->mode != AUDIO_MODE_NORMAL) {
             vc_usecase = get_usecase_from_list(adev,
                                                get_usecase_id_from_usecase_type(adev, VOICE_CALL));
-            if (((vc_usecase) && ((vc_usecase->devices & AUDIO_DEVICE_OUT_ALL_CODEC_BACKEND) &&
-                                 (usecase->devices & AUDIO_DEVICE_OUT_ALL_CODEC_BACKEND))) ||
-                                (usecase->devices == AUDIO_DEVICE_IN_VOICE_CALL)) {
+            if ((vc_usecase) && (((vc_usecase->devices & AUDIO_DEVICE_OUT_ALL_CODEC_BACKEND) &&
+                                 (usecase->devices & AUDIO_DEVICE_OUT_ALL_CODEC_BACKEND)) ||
+                                (usecase->devices == AUDIO_DEVICE_IN_VOICE_CALL))) {
                 in_snd_device = vc_usecase->in_snd_device;
                 out_snd_device = vc_usecase->out_snd_device;
             }