Interface: Remove NS RTOS specific implementation

Move NS RTOS related interface code to tf-m-test to decouple TF-M from
NS specific implementation.
The removed code includes OS wrapper headers and RTOS specific
implementation.

Export tfm_ns_interface_dispatch() to NS as API to integrate with TF-M
NS interface.
Add an example of tfm_ns_interface_dispatch() implementation.

Change-Id: I9b331c32ac26551bfdbc4996eecd08efc7d7c2c3
Signed-off-by: David Hu <david.hu@arm.com>
diff --git a/interface/include/tfm_ns_interface.h b/interface/include/tfm_ns_interface.h
index 1dd0692..fa0cc31 100644
--- a/interface/include/tfm_ns_interface.h
+++ b/interface/include/tfm_ns_interface.h
@@ -24,11 +24,14 @@
  *          desired veneer function, to be called with the parameters
  *          described from arg0 to arg3.
  *
+ * \note    NSPE shall implement this dispatcher according to NS specific
+ *          implementation and actual usage scenario.
+ *
  * \param[in] fn   Function pointer to the veneer function desired
- * \param[in] arg0 Argument 0
- * \param[in] arg1 Argument 1
- * \param[in] arg2 Argument 2
- * \param[in] arg3 Argument 3
+ * \param[in] arg0 Argument 0 of fn
+ * \param[in] arg1 Argument 1 of fn
+ * \param[in] arg2 Argument 2 of fn
+ * \param[in] arg3 Argument 3 of fn
  *
  * \return Returns the same return value of the requested veneer function
  *
@@ -40,17 +43,6 @@
                                   uint32_t arg0, uint32_t arg1,
                                   uint32_t arg2, uint32_t arg3);
 
-/**
- * \brief NS interface, Initialise the NS interface
- *
- * \details This function needs to be called from the NS world to
- *          properly initialise the NS interface towards TF-M. This
- *          function will initialise all the objects required for
- *          runtime dispatching of TF-M requests to services
- *
- * \return  A value according to \ref enum tfm_status_e
- */
-enum tfm_status_e tfm_ns_interface_init(void);
 #ifdef __cplusplus
 }
 #endif