GSD-2021-1002696 tee: amdtee: fix an IS_ERR() vs NULL bug

tee: amdtee: fix an ISERR vs NULL bug 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 v5.10.88 by commit 640e28d618e82be78fb43b4bf5113bc90d6aa44...