ci: ommit oot Intel driver (fails on 22.04)

This is a problem in the Intel out-of-tree /dev/isgx code, not SGX-Step. Most
platforms are using the in-tree /dev/sgx_enclave Linux driver anyway nowadays,
so simply skip building /dev/isgx in the CI for now.

For reference, the CI log:

make -C /lib/modules/6.5.0-1015-azure/build M=/home/runner/work/sgx-step/sgx-step/kernel/linux-sgx-driver modules
make[1]: Entering directory '/usr/src/linux-headers-6.5.0-1015-azure'
warning: the compiler differs from the one used to build the kernel
  The kernel was built by: x86_64-linux-gnu-gcc-11 (Ubuntu 11.4.0-1ubuntu1~22.04) 11.4.0
  You are using:           gcc-11 (Ubuntu 11.4.0-1ubuntu1~22.04) 11.4.0
  CC [M]  /home/runner/work/sgx-step/sgx-step/kernel/linux-sgx-driver/sgx_main.o
/home/runner/work/sgx-step/sgx-step/kernel/linux-sgx-driver/sgx_main.c: In function ‘sgx_mmap’:
/home/runner/work/sgx-step/sgx-step/kernel/linux-sgx-driver/sgx_main.c:112:23: error: assignment of read-only member ‘vm_flags’
  112 |         vma->vm_flags |= VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP | VM_IO |
      |                       ^~
make[3]: *** [scripts/Makefile.build:251: /home/runner/work/sgx-step/sgx-step/kernel/linux-sgx-driver/sgx_main.o] Error 1
make[2]: *** [/usr/src/linux-headers-6.5.0-1015-azure/Makefile:2039: /home/runner/work/sgx-step/sgx-step/kernel/linux-sgx-driver] Error 2
make[1]: *** [Makefile:234: __sub-make] Error 2
make[1]: Leaving directory '/usr/src/linux-headers-6.5.0-1015-azure'

.github/workflows/ci.yaml

@@ -19,10 +19,15 @@ jobs:
       - name: Check out repository
         uses: actions/checkout@v2
 
+      - name: Fetch submodules
+        run: |
+          git submodule init
+          git submodule update
+
       - name: Build and load /dev/sgx-step
         run: |
           cd $GITHUB_WORKSPACE/kernel/
-          ./install_SGX_driver.sh
+          #./install_SGX_driver.sh
           make clean load
 
       - name: Patch and install SGX SDK