Document block store encryption

Change-Id: Id86c5a62d812b8089d6b80720a8c36424b72ba94
Signed-off-by: Gabor Toth <gabor.toth2@arm.com>
diff --git a/docs/services/index.rst b/docs/services/index.rst
index 5f7377d..15e2415 100644
--- a/docs/services/index.rst
+++ b/docs/services/index.rst
@@ -9,7 +9,7 @@
     crypto-service-description
     fwu/index
     secure-storage-service-description
-    block-storage-service-description
+    block-storage/block-storage-service-description
     uefi-smm-services
     logging-service-description