.github/zephyr.yml: separate platforms a bit

It's faster like this and we also want platform-specific failures to be
identify as such and not block compilation of other platforms.

Also removed obsolete comment that sneaked in previous commit by
mistake and remove duplicate "zephyr" in the job name.

Signed-off-by: Marc Herbert <marc.herbert@intel.com>

.github/workflows/zephyr.yml

@@ -8,7 +8,7 @@ name: Zephyr
 on: [push, pull_request, workflow_dispatch]
 
 jobs:
-  zephyr-build:
+  build:
     runs-on: ubuntu-20.04
 
     strategy:
@@ -19,8 +19,13 @@ jobs:
           "https://github.com/zephyrproject-rtos/zephyr  main",
         ]
         IPC_platforms: [
-          -a,  # IPC3 everything
-          -i IPC4 tgl,  # only tgl has IPC4 overlay file now
+          # IPC3
+          apl cnl,
+          icl jsl,
+          tgl tgl-h,
+          imx8 imx8x imx8m,
+          # only tgl has IPC4 overlay file now
+          -i IPC4 tgl,
         ]
 
     steps:
@@ -35,7 +40,6 @@ jobs:
                west update --narrow --fetch-opt=--depth=5
 
       - name: select zephyr revision
-        # ignore failures when fetching local refs like "manifest-rev"
         run: cd workspace/zephyr/ &&
              if [ 'manifest_revision' != '${{ matrix.zephyr_revision }}' ]; then
                  git fetch --depth 5 ${{ matrix.zephyr_revision }} &&