build(changelog): add new scope for Arm SMMU driver

Added new scope for Arm SMMU driver.

Signed-off-by: Manish V Badarkhe <manish.badarkhe@arm.com>
Change-Id: I62f5ed36657a071d125cdddacbff9fb23d2bc8e0
diff --git a/changelog.yaml b/changelog.yaml
index add81ef..e94c30a 100644
--- a/changelog.yaml
+++ b/changelog.yaml
@@ -645,6 +645,9 @@
                   - title: GIC-600AE
                     scope: gic600ae
 
+          - title: SMMU
+            scope: smmu
+
           - title: TZC
             scope: tzc