KVM x86/pmu changes for 6.11

 - Don't advertise IA32_PERF_GLOBAL_OVF_CTRL as an MSR-to-be-saved, as it reads
   '0' and writes from userspace are ignored.

 - Update to the newfangled Intel CPU FMS infrastructure.

 - Use macros instead of open-coded literals to clean up KVM's manipulation of
   FIXED_CTR_CTRL MSRs.