fs: jfs: fix shift-out-of-bounds in dbDiscardAG
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 v5.15.86 by commit 10b87da8fae79c7daf5eda6a9e4f1d31b85b4d92. For more details please see the references link.