GSD-2023-1000845 lib/fonts: fix undefined behavior in bit shift for get_default_font

fix undefined behavior in bit shift for get_default_font 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 9c14a85e18a58c102ec223144b7edb5b345c1bea, it was introduced in version v2.6.23 by commit c81f717cb9e0bd91dc4b98753cb2705ab0fe2801. For more details please see the references link