docs: change all occurrences of RSS to RSE

Changes all occurrences of "RSS" and "rss" in the documentation
to "RSE" and "rse".

Signed-off-by: Tamas Ban <tamas.ban@arm.com>
Change-Id: Ia42078f5faa1db331b1e5a35f01faeaf1afacb5f
diff --git a/docs/threat_model/firmware_threat_model/index.rst b/docs/threat_model/firmware_threat_model/index.rst
index 05b6710..ce1752f 100644
--- a/docs/threat_model/firmware_threat_model/index.rst
+++ b/docs/threat_model/firmware_threat_model/index.rst
@@ -30,7 +30,7 @@
    threat_model
    threat_model_el3_spm
    threat_model_fvp_r
-   threat_model_rss_interface
+   threat_model_rse_interface
    threat_model_arm_cca
    threat_model_fw_update_and_recovery