tty: synclinkgt: Fix null-pointer-dereference in slgtclean()
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 ddd67751ab86c6a65f95c35293c42f85a42ac05d. For more details please see the references link.