Some cleanup

* Prefer default initializer over std::memset 0 when possible and more readable.
* Use std::format in trophy files name obtaining.
* Use vm::ptr<>::operator bool() instead of comparing vm::ptr to vm::null or using addr().
* Add a few std::memset calls in hle where it matters (or in some places just to document an actual firmware memcpy call).

rpcs3/Emu/Cell/Modules/cellKb.cpp

@@ -251,6 +251,8 @@ error_code cellKbGetInfo(vm::ptr<CellKbInfo> info)
 	if (!info)
 		return CELL_KB_ERROR_INVALID_PARAMETER;
 
+	std::memset(info.get_ptr(), 0, info.size());
+
 	std::lock_guard<std::mutex> lock(handler->m_mutex);
 
 	const KbInfo& current_info = handler->GetInfo();