CVE-2026-72105 dm-log: fix a bitset_size overflow on 32bit machines

In the Linux kernel, the following vulnerability has been resolved: dm-log: fix a bitsetsize overflow on 32bit machines Commit c20e36b7631d "dm log: fix out-of-bounds write due to regioncount overflow" made sure that regioncount could fit in an unsigned int. But the bitmap memory isn't allocated...