amt: fix possible null-ptr-deref in amt_rcv()
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 v5.17.15 by commit 42c6af92666a6f4a600a0f03fabce98a361dc824, it was introduced in version v5.17.15 by commit 60d9c020c69977e138727b3577bc6a0458325e9c. For more details please see the references link.