ci: Use crosskit submodules

This commit updates the CI workflow to use the "cross compilation kit"
submodules, instead of directly checking out the crosskit repositories.

Note that the new crosskit submodule repositories are hosted by
`zephyrproject-rtos` instead of `stephanosio`.

Signed-off-by: Stephanos Ioannidis <[email protected]>

Author: stephanosio

.github/workflows/ci.yml

@@ -540,13 +540,8 @@ jobs:
 
         # Install dependencies for cross compilation
         if [ "${{ matrix.host.name }}" == "macos-x86_64" ]; then
-          # Clone AArch64-x86 crosskit
-          git clone \
-            https://github.com/stephanosio/crosskit-x86_64-apple-darwin.git \
-            ${WORKSPACE}/crosskit
-
           # Make crosskit available in PATH
-          echo "${WORKSPACE}/crosskit/scripts" >> $GITHUB_PATH
+          echo "${GITHUB_WORKSPACE}/crosskit/crosskit-x86_64-apple-darwin/scripts" >> $GITHUB_PATH
         fi
 
         # Make Python 3.8 available in PATH
@@ -697,23 +692,15 @@ jobs:
         EOF
 
         if [ "${{ matrix.host.name }}" == "macos-x86_64" ]; then
-          # Clone crosskit-x86_64-darwin-libpython cross compilation kit
-          git clone \
-            https://github.com/stephanosio/crosskit-x86_64-darwin-libpython.git \
-            ${WORKSPACE}/crosskit-x86_64-darwin-libpython
           # Use Python 3.8.12
-          export LIBPYTHON_KIT_ROOT=${WORKSPACE}/crosskit-x86_64-darwin-libpython/python-3.8.12
+          export LIBPYTHON_KIT_ROOT=${GITHUB_WORKSPACE}/crosskit/crosskit-x86_64-darwin-libpython/python-3.8.12
           # Set Python configuration resolver for GDB
           cat <<EOF >> .config
         CT_GDB_CROSS_PYTHON_BINARY="${LIBPYTHON_KIT_ROOT}/bin/python"
         EOF
         elif [ "${{ matrix.host.name }}" == "windows-x86_64" ]; then
-          # Clone crosskit-mingw-w64-libpython cross compilation kit
-          git clone \
-            https://github.com/stephanosio/crosskit-mingw-w64-libpython.git \
-            ${WORKSPACE}/crosskit-mingw-w64-libpython
           # Use Python 3.8.3
-          export LIBPYTHON_KIT_ROOT=${WORKSPACE}/crosskit-mingw-w64-libpython/python-3.8.3
+          export LIBPYTHON_KIT_ROOT=${GITHUB_WORKSPACE}/crosskit/crosskit-mingw-w64-libpython/python-3.8.3
           # Set Python configuration resolver for GDB
           cat <<EOF >> .config
         CT_GDB_CROSS_PYTHON_BINARY="${LIBPYTHON_KIT_ROOT}/bin/python"