hal: fix compilation error for 8952 hal

Fix 'idx' undeclared

Change-Id: I647d74e63566403e2f3118e600d50cc22b402655
diff --git a/hal/msm8916/platform.c b/hal/msm8916/platform.c
index 3a8f314..9613914 100644
--- a/hal/msm8916/platform.c
+++ b/hal/msm8916/platform.c
@@ -1237,6 +1237,10 @@
     const char *snd_card_name;
     char mixer_xml_path[100],ffspEnable[PROPERTY_VALUE_MAX];
     char *cvd_version = NULL;
+    int idx;
+
+    my_data = calloc(1, sizeof(struct platform_data));
+
     if (!my_data) {
         ALOGE("failed to allocate platform data");
         return NULL;