Add entry for 6.12 kernel in manifest

BUG=b/402287494
TEST=repo sync --manifest-name=$HOME/cos/manifest/external_full.xml
RELEASE_NOTE=None

Change-Id: I5305582c50cc2ed20bbe7a4ecf5e0d9f3df481e6
Reviewed-on: https://cos-review.googlesource.com/c/cos/manifest/+/95699
Tested-by: Kevin Berry <kpberry@google.com>
Reviewed-by: Anil Altinay <aaltinay@google.com>
diff --git a/external_full.xml b/external_full.xml
index 91c6d60..10cbe5a 100644
--- a/external_full.xml
+++ b/external_full.xml
@@ -192,15 +192,15 @@
   <project path="src/third_party/toolbox"
            name="third_party/toolbox"
            revision="refs/heads/main" />
-  <project path="src/third_party/kernel/v5.15"
-           name="third_party/kernel"
-           revision="refs/heads/cos-5.15" />
   <project path="src/third_party/kernel/v6.1"
            name="third_party/kernel"
            revision="refs/heads/cos-6.1" />
   <project path="src/third_party/kernel/v6.6"
            name="third_party/kernel"
            revision="refs/heads/cos-6.6" />
+  <project path="src/third_party/kernel/v6.12"
+           name="third_party/kernel"
+           revision="refs/heads/cos-6.12" />
 
   <repo-hooks enabled-list="pre-upload"
            in-project="cos/repohooks" />