doc: security/etsi: Provision 5.13.1 assessment

Add self-assessment for provision 5.13.1

Signed-off-by: Flavio Ceolin <flavio.ceolin@intel.com>

doc/kernel/usermode/syscalls.rst

@@ -335,6 +335,8 @@ If any check fails, the macros will return a nonzero value. The macro
 calling thread. This is done instead of returning some error condition to
 keep the APIs the same when calling from supervisor mode.
 
+.. _syscall_verification:
+
 Verifier Definition
 ===================
 

doc/security/standards/etsi-303645.rst

@@ -683,8 +683,8 @@ Provisions Assessment
         transferred via Application Programming Interfaces (APIs) or between networks in
         services and devices.
       - M
-      -
-      -
+      - Y
+      - :ref:`Syscall verification <syscall_verification>` and :ref:`Coding guidelines <coding_guidelines>`
 
         .. _ETSI_Provision_6_1_1:
     * - Provision 6.1-1