CVE-2026-63836 batman-adv: tp_meter: avoid divide-by-zero for dec_cwnd

In the Linux kernel, the following vulnerability has been resolved: batman-adv: tpmeter: avoid divide-by-zero for deccwnd The cwnd is always MSS = cwnd = 0x20000000. But the calculation in batadvtpupdatecwnd assumes unsigned 32 bit arithmetics. mss 8 2 / cwnd 8 In case cwnd is actually 0x20000000...