Bluetooth: Adds SMP response timer for security request

This adds timer to cancel security request from remote if there
is no response from user for pairing popup.

Change-Id: I18694dcc5275a1eb10de4ad921b6baca189b42fa
diff --git a/stack/smp/smp_act.c b/stack/smp/smp_act.c
index 1f1eb6e..04c3a80 100644
--- a/stack/smp/smp_act.c
+++ b/stack/smp/smp_act.c
@@ -338,6 +338,9 @@
             p_cb->peer_auth_req = auth_req;
             p_cb->loc_r_key = p_cb->loc_i_key = SMP_SEC_DEFAULT_KEY ;
             p_cb->cb_evt = SMP_SEC_REQUEST_EVT;
+            btu_stop_timer (&p_cb->rsp_timer_ent);
+            btu_start_timer (&p_cb->rsp_timer_ent, BTU_TTYPE_SMP_PAIRING_CMD,
+                   SMP_WAIT_FOR_RSP_TOUT);
             break;
 
         case BTM_BLE_SEC_REQ_ACT_DISCARD: