workflows: Use native arm64 runners

Use native arm64 runners to speed up build process. Cross compile is
still used for arm targets, but also benefit from the arm64 runner
architecture. Overall build time will be reduced by 25 to 30 minutes by
this.

Signed-off-by: Nicolai Buchwitz <nb@tipi-net.de>

.github/workflows/kernel-build.yml

@@ -16,7 +16,7 @@ env:
 
 jobs:
   build:
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-24.04-arm
     strategy:
       matrix:
         include:
@@ -56,17 +56,13 @@ jobs:
             kernel: kernel_2712
 
     steps:
-    - name: Update install
-      run:
+    - name: Install armhf crossbuild toolchain
+      if: matrix.arch == 'arm'
+      env:
+        DEBIAN_FRONTEND: noninteractive
+      run: |
         sudo apt-get update
-
-    - name: Install toolchain
-      run:
-        if [[ "${{matrix.arch}}" == "arm64" ]]; then
-          sudo apt-get install gcc-aarch64-linux-gnu;
-        else
-          sudo apt-get install gcc-arm-linux-gnueabihf;
-        fi
+        sudo apt-get install -y gcc-arm-linux-gnueabihf
       timeout-minutes: 15
 
     - uses: actions/checkout@v4
@@ -79,7 +75,6 @@ jobs:
         mkdir ${{github.workspace}}/build
         export ARCH=${{matrix.arch}}
         if [[ "$ARCH" == "arm64" ]]; then
-          export CROSS_COMPILE=aarch64-linux-gnu-
           export DTS_SUBDIR=broadcom
           export IMAGE=Image.gz
         else