CVE-2024-48881 bcache: revert replacing IS_ERR_OR_NULL with IS_ERR again

In the Linux kernel, the following vulnerability has been resolved: bcache: revert replacing ISERRORNULL with ISERR again Commit 028ddcac477b "bcache: Remove unnecessary NULL point check in node allocations" leads a NULL pointer deference in cachesetflush. 1721 if !ISERRORNULLc-root 1722...