feat(neoverse-rd): add scope for RD-V1-MC

As RD-V1-MC would need a dedicated scope for use, define the scope
'rdv1mc' under the subsection within Neoverse-RD platforms.

Change-Id: I5fd53ce89815e355b595fe7ff066386842b7af03
Signed-off-by: Rohit Mathew <rohit.mathew@arm.com>
diff --git a/changelog.yaml b/changelog.yaml
index 60a6349..527a6b7 100644
--- a/changelog.yaml
+++ b/changelog.yaml
@@ -228,6 +228,9 @@
               - title: RD-V1
                 scope: rdv1
 
+              - title: RD-V1-MC
+                scope: rdv1mc
+
               - title: RD-N2
                 scope: rdn2