[mono] Add missing return in mono_type_to_load_membase (#106798)

There was a missing return for MONO_TYPE_VALUETYPE in mono_type_to_load_membase. It works correctly even without this fix but only by coincidence because the following case is MONO_TYPE_TYPEDBYREF which returns the same OP_LOADV_MEMBASE op code.

src/mono/mono/mini/mini.c

@@ -420,6 +420,7 @@ mono_type_to_load_membase (MonoCompile *cfg, MonoType *type)
 	case MONO_TYPE_VALUETYPE:
 		if (mini_class_is_simd (cfg, mono_class_from_mono_type_internal (type)))
 			return OP_LOADX_MEMBASE;
+		return OP_LOADV_MEMBASE;
 	case MONO_TYPE_TYPEDBYREF:
 		return OP_LOADV_MEMBASE;
 	case MONO_TYPE_GENERICINST: