doc: security/etsi: Provision 5.3.12 assessment

Add self-assessment for provision 5.3.12

Signed-off-by: Flavio Ceolin <flavio.ceolin@intel.com>
diff --git a/doc/security/standards/etsi-303645.rst b/doc/security/standards/etsi-303645.rst
index f829f7a..5e5f275 100644
--- a/doc/security/standards/etsi-303645.rst
+++ b/doc/security/standards/etsi-303645.rst
@@ -347,8 +347,8 @@
       - The device should notify the user when the application of a software update
         will disrupt the basic functioning of the device.
       - R C
-      -
-      -
+      - N/A
+      - Zephyr provides this information for its updates. Anyone using Zephyr in their products must check if they are affected
 
         .. _ETSI_Provision_5_3_13:
     * - Provision 5.3-13