riscv, bpf: Fix potential NULL dereference
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 v5.15 by commit 27de809a3d83a6199664479ebb19712533d6fd9b, it was introduced in version v5.7 by commit ca6cb5447ceca6a87d6b62c9e5d41042c34f7ffa. For more details please see the references link.