qcacmn: Add API to allow WMI commands

Add API to restart sending WMI commands after they have been
stopped using wmi_stop() API.

Change-Id: Id65e5d1310cd7076ca47c6e7e19221492c10a868

wmi/inc/wmi_unified_api.h

@@ -442,6 +442,14 @@ void wmi_set_tgt_assert(wmi_unified_t wmi_handle, bool val);
 int
 wmi_stop(wmi_unified_t wmi_handle);
 
+/**
+ * generic function to start unified WMI command
+ * @param wmi_handle      : handle to WMI.
+ * @return 0  on success and -ve on failure.
+ */
+int
+wmi_start(wmi_unified_t wmi_handle);
+
 /**
  * API to flush all the previous packets  associated with the wmi endpoint
  *