openpower-pels: clean up various compile warnings

Compile warnings observed when compiling parts of the
openpower-pels (or corresponding tests) under stricter
compiler warning flags of Meson.

Issues fixed:
    - many unused parameters
    - invalid case fall-through
    - excess semi-colons
    - incorrect 'const' on return-by-value type
    - removal of variable length array in test case
    - uncaught return from 'system' call in test case

Signed-off-by: Patrick Williams <patrick@stwcx.xyz>
Change-Id: I8af69184042cf8661d1307a02ecf3afcab4724a1
diff --git a/extensions/openpower-pels/entry_points.cpp b/extensions/openpower-pels/entry_points.cpp
index 7d931e6..4be961b 100644
--- a/extensions/openpower-pels/entry_points.cpp
+++ b/extensions/openpower-pels/entry_points.cpp
@@ -29,7 +29,7 @@
 
 std::unique_ptr<Manager> manager;
 
-DISABLE_LOG_ENTRY_CAPS();
+DISABLE_LOG_ENTRY_CAPS()
 
 void pelStartup(internal::Manager& logManager)
 {
@@ -53,7 +53,7 @@
 #endif
 }
 
-REGISTER_EXTENSION_FUNCTION(pelStartup);
+REGISTER_EXTENSION_FUNCTION(pelStartup)
 
 void pelCreate(const std::string& message, uint32_t id, uint64_t timestamp,
                Entry::Level severity, const AdditionalDataArg& additionalData,
@@ -63,21 +63,21 @@
                     ffdc);
 }
 
-REGISTER_EXTENSION_FUNCTION(pelCreate);
+REGISTER_EXTENSION_FUNCTION(pelCreate)
 
 void pelDelete(uint32_t id)
 {
     return manager->erase(id);
 }
 
-REGISTER_EXTENSION_FUNCTION(pelDelete);
+REGISTER_EXTENSION_FUNCTION(pelDelete)
 
 void pelDeleteProhibited(uint32_t id, bool& prohibited)
 {
     prohibited = manager->isDeleteProhibited(id);
 }
 
-REGISTER_EXTENSION_FUNCTION(pelDeleteProhibited);
+REGISTER_EXTENSION_FUNCTION(pelDeleteProhibited)
 
 } // namespace pels
 } // namespace openpower