Fix VTS test case HidlHalGTest#RadioHidlTest.getIccCardStatus_32bit failed.

In the ril.h, the annotation of gsm_umts_subscription_app_index is "value < RIL_CARD_MAX_APPS, -1 if none".
But in the reference-ril.c, the gsm_umts_subscription_app_index is initialized to RIL_CARD_MAX_APPS.
The VTS test case HidlHalGTest#RadioHidlTest.getIccCardStatus_32bit failed with the reason :"Expected: (cardStatus.gsmUmtsSubscriptionAppIndex) < ((int)RadioConst::CARD_MAX_APPS), actual: 8 vs 8"
gsm_umts_subscription_app_index; /* value < RIL_CARD_MAX_APPS, -1 if none */
cdma_subscription_app_index;     /* value < RIL_CARD_MAX_APPS, -1 if none */
ims_subscription_app_index;      /* value < RIL_CARD_MAX_APPS, -1 if none */

Test:build
Change-Id: I3f7ade93e2f0f7099d934a1b50e01ff04c8c01da
diff --git a/reference-ril/reference-ril.c b/reference-ril/reference-ril.c
index 59bb372..16e379a 100644
--- a/reference-ril/reference-ril.c
+++ b/reference-ril/reference-ril.c
@@ -2721,9 +2721,9 @@
     RIL_CardStatus_v6 *p_card_status = malloc(sizeof(RIL_CardStatus_v6));
     p_card_status->card_state = card_state;
     p_card_status->universal_pin_state = RIL_PINSTATE_UNKNOWN;
-    p_card_status->gsm_umts_subscription_app_index = RIL_CARD_MAX_APPS;
-    p_card_status->cdma_subscription_app_index = RIL_CARD_MAX_APPS;
-    p_card_status->ims_subscription_app_index = RIL_CARD_MAX_APPS;
+    p_card_status->gsm_umts_subscription_app_index = -1;
+    p_card_status->cdma_subscription_app_index = -1;
+    p_card_status->ims_subscription_app_index = -1;
     p_card_status->num_applications = num_apps;
 
     // Initialize application status