s390/ctcm: Fix return type of ctc{mp,}m_tx()
This is an automated ID intended to aid in discovery of potential security vulnerabilities. The actual impact and attack plausibility have not yet been proven. This ID is fixed in Linux Kernel version v6.0.16 by commit 23f145dcc1dfb9012f94b67be9e0128b45dc8490. For more details please see the references link.