llama : remove MPI backend (#7395)

.github/workflows/build.yml

@@ -306,40 +306,6 @@ jobs:
           cd build
           ctest -L main --verbose --timeout 900
 
-  ubuntu-latest-cmake-mpi:
-    runs-on: ubuntu-latest
-
-    continue-on-error: true
-
-    strategy:
-      matrix:
-        mpi_library: [mpich, libopenmpi-dev]
-
-    steps:
-      - name: Clone
-        id: checkout
-        uses: actions/checkout@v4
-
-      - name: Dependencies
-        id: depends
-        run: |
-          sudo apt-get update
-          sudo apt-get install build-essential ${{ matrix.mpi_library }}
-
-      - name: Build
-        id: cmake_build
-        run: |
-          mkdir build
-          cd build
-          cmake -DLLAMA_MPI=ON ..
-          cmake --build . --config Release -j $(nproc)
-
-      - name: Test
-        id: cmake_test
-        run: |
-          cd build
-          ctest -L main --verbose
-
   ubuntu-latest-cmake-rpc:
     runs-on: ubuntu-latest