FIX cpplint errors

.pre-commit-config.yaml

@@ -1,4 +1,4 @@
-files: ^main.cpp|^static_scheduling|^static_scheduling_with_event|^TESTS
+files: ^main.cpp|^static_scheduling|^static_scheduling_with_event|^TESTS|^multi_tasking
 repos:
   - repo: https://github.com/pre-commit/pre-commit-hooks
     rev: v4.3.0
@@ -22,6 +22,5 @@ repos:
       - id: cppcheck
         name: cppcheck
         require_serial: true
-        entry: cppcheck --enable=all --suppress=missingInclude --inline-suppr -i mbed-os --std=c++14 --error-exitcode=1
-        # --suppress=missingIncludeSystem
+        entry: cppcheck --enable=all --suppress=missingInclude --suppress=missingIncludeSystem --suppress=unusedFunction --inline-suppr -i mbed-os --std=c++14 --error-exitcode=1
         language: system