CI: kernel: don't checkout and install feeds

We don't need to checkout feed and install feeds for kernel tests. This
saves up to 2 minutes for each target kernel build test.

Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>

.github/workflows/kernel.yml

@@ -68,7 +68,6 @@ jobs:
     with:
       target: ${{ matrix.target }}
       build_all_kmods: true
-      include_feeds: true
 
   check-kernel-patches:
     name: Check Kernel patches