[openwrt/openwrt] CI: build: drop redundant generate ccache hash job

[LEDE Commits]

ansuel pushed a commit to openwrt/openwrt.git, branch openwrt-23.05:
https://git.openwrt.org/6420851c0c4241d075600662612b3ca4d8906bcd

commit 6420851c0c4241d075600662612b3ca4d8906bcd
Author: Christian Marangi <ansuelsmth at gmail.com>
AuthorDate: Sat May 27 22:08:26 2023 +0200

    CI: build: drop redundant generate ccache hash job
    
    Drop redundant generare ccache hash job as that can be done by
    integrated github expressions to generate an hash.
    The only change is that the integrated way generate a sha256 hash
    instead of an md5 sum.
    
    Signed-off-by: Christian Marangi <ansuelsmth at gmail.com>
    (cherry picked from commit 457f6b0b9c07772f529a9714a974f3eb74f9b99d)
---
 .github/workflows/build.yml | 10 +---------
 1 file changed, 1 insertion(+), 9 deletions(-)

diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 816ef6ab3c..eba4df7e91 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -57,7 +57,6 @@ jobs:
     runs-on: ubuntu-latest
     outputs:
       owner_lc: ${{ steps.lower_owner.outputs.owner_lc }}
-      ccache_hash: ${{ steps.ccache_hash.outputs.ccache_hash }}
       container_tag: ${{ steps.determine_tools_container.outputs.container_tag }}
 
     steps:
@@ -76,13 +75,6 @@ jobs:
 
           echo "owner_lc=$OWNER_LC" >> $GITHUB_OUTPUT
 
-      - name: Generate ccache hash
-        id: ccache_hash
-        run: |
-          CCACHE_HASH=$(md5sum include/kernel-* | awk '{ print $1 }' \
-           | md5sum | awk '{ print $1 }')
-          echo "ccache_hash=$CCACHE_HASH" >> $GITHUB_OUTPUT
-
       # Per branch tools container tag
       # By default stick to latest
       # For official test targetting openwrt stable branch
@@ -231,7 +223,7 @@ jobs:
         uses: actions/cache at v3
         with:
           path: openwrt/.ccache
-          key: ccache-kernel-${{ inputs.target }}/${{ inputs.subtarget }}-${{ needs.setup_build.outputs.ccache_hash }}
+          key: ccache-kernel-${{ inputs.target }}/${{ inputs.subtarget }}-${{ hashFiles('openwrt/include/kernel-**') }}
           restore-keys: |
             ccache-kernel-${{ inputs.target }}/${{ inputs.subtarget }}-