workflows: linux: Fix duplicate contents perm

GitHub is now stricter about this useless and bogus repetition.

Signed-off-by: Loïc Minier <[email protected]>

Author: lool

.github/workflows/linux.yml

@@ -10,7 +10,6 @@ on:
 # implicitely set all other permissions to none
 permissions:
   contents: read # actions/checkout debos.yml test.yml
-  contents: read # debos.yml lava-schema-check.yml test.yml
   packages: read # test.yml
   pull-requests: write # test.yml