kernel/process: Make CodeSet a regular non-inherited object

These only exist to ferry data into a Process instance and end up going
out of scope quite early. Because of this, we can just make it a plain
struct for holding things and just std::move it into the relevant
function. There's no need to make this inherit from the kernel's Object
type.

src/core/hle/kernel/object.cpp

@@ -25,7 +25,6 @@ bool Object::IsWaitable() const {
     case HandleType::Process:
     case HandleType::AddressArbiter:
     case HandleType::ResourceLimit:
-    case HandleType::CodeSet:
     case HandleType::ClientPort:
     case HandleType::ClientSession:
         return false;