Revert "overrides: pin kernel-6.8.11-300.fc40"

This reverts commit 8d4e788.

Now that we shipped bootloader updates for Secure Boot systems, we no
longer need to pin to v6.8.

See also: coreos/fedora-coreos-tracker#1752

manifest-lock.overrides.yaml

@@ -19,26 +19,6 @@ packages:
     metadata:
       bodhi: https://bodhi.fedoraproject.org/updates/FEDORA-2024-f2e6b90acd
       type: fast-track
-  kernel:
-    evr: 6.8.11-300.fc40
-    metadata:
-      reason: https://github.com/coreos/fedora-coreos-tracker/issues/1752
-      type: pin
-  kernel-core:
-    evr: 6.8.11-300.fc40
-    metadata:
-      reason: https://github.com/coreos/fedora-coreos-tracker/issues/1752
-      type: pin
-  kernel-modules:
-    evr: 6.8.11-300.fc40
-    metadata:
-      reason: https://github.com/coreos/fedora-coreos-tracker/issues/1752
-      type: pin
-  kernel-modules-core:
-    evr: 6.8.11-300.fc40
-    metadata:
-      reason: https://github.com/coreos/fedora-coreos-tracker/issues/1752
-      type: pin
   openssh:
     evr: 9.6p1-1.fc40.4
     metadata: