ci: fix kernel sync check

Author: BennoLossin

.github/workflows/kernel.yml

@@ -14,12 +14,8 @@ jobs:
         with:
           ref: kernel
           path: pin-init
-      - uses: actions/checkout@v4
-        with:
-          repository: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
-          ref: master
-          path: kernel
-          fetch-depth: 1
+      - run: git clone --depth 1 git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
       - run: |
-          cp -r kernel/rust/pin-init .
+          cp -r linux/rust/pin-init .
+          cd pin-init
           git diff --quiet && git diff --cached --quiet && [ -z "$(git ls-files --others --exclude-standard)" ]