CVE-2026-64250 LoongArch: Report dying CPU to RCU in stop_this_cpu()

In the Linux kernel, the following vulnerability has been resolved: LoongArch: Report dying CPU to RCU in stopthiscpu This is a port of MIPS commit 9f3f3bdc6d9dac1 "MIPS: smp: report dying CPU to RCU in stopthiscpu". smpsendstop parks all secondary CPUs in stopthiscpu. And the function marks the...