audio: Fix compilation issue on HFP disable

- Fix compilation issue

Change-Id: I0f4a219da1fe71cfc921215498952d797ae0f6d7
diff --git a/hal/msm8916/platform.c b/hal/msm8916/platform.c
index e932667..73689eb 100644
--- a/hal/msm8916/platform.c
+++ b/hal/msm8916/platform.c
@@ -4345,7 +4345,6 @@
 int platform_set_parameters(void *platform, struct str_parms *parms)
 {
     struct platform_data *my_data = (struct platform_data *)platform;
-    struct audio_device *adev = my_data->adev;
     char value[256] = {0};
     int len;
     int ret = 0, err;
@@ -4462,7 +4461,7 @@
     native_audio_set_params(platform, parms, value, sizeof(value));
     audio_extn_spkr_prot_set_parameters(parms, value, len);
     audio_extn_usb_set_sidetone_gain(parms, value, len);
-    audio_extn_hfp_set_parameters(adev, parms);
+    audio_extn_hfp_set_parameters(my_data->adev, parms);
     true_32_bit_set_params(parms, value, len);
     ALOGV("%s: exit with code(%d)", __func__, ret);
     return ret;