feat(plat/fvp_r):  Threat Model for TF-A v8-R64 Support

Threat model for the current, BL1-only R-class support.

Signed-off-by: Gary Morrison <gary.morrison@arm.com>
Change-Id: I8479d5cb30f3cf3919281cc8dc1f21cada9511e0
diff --git a/docs/threat_model/threat_model_spm.rst b/docs/threat_model/threat_model_spm.rst
index 4db4c66..a7bc2a9 100644
--- a/docs/threat_model/threat_model_spm.rst
+++ b/docs/threat_model/threat_model_spm.rst
@@ -1,4 +1,4 @@
-SPMC threat model
+SPMC Threat Model
 *****************
 
 ************************