config: trees: Add CIP v6.12 branch

At this time there is no plan for a realtime (-rt) branch for 6.12.y.
So only add the non -rt version.

Signed-off-by: Chris Paterson <[email protected]>

Author: patersonc

config/trees.yaml

@@ -465,6 +465,10 @@ build_configs:
     <<: *cip
     branch: 'linux-6.1.y-cip-rt'
 
+  cip-6.12:
+    <<: *cip
+    branch: 'linux-6.12.y-cip'
+
   clk:
     <<: *base-arm
     tree: clk