KVM: x86/pmu: Implement AMD mediated PMU requirements

KVM: x86/pmu: Implement AMD mediated PMU requirements

Require host PMU version 2+ for AMD mediated PMU support, as
PERF_GLOBAL_CTRL and friends are hard requirements for the mediated PMU.

Signed-off-by: Dapeng Mi <dapeng1.mi@linux.intel.com>
Co-developed-by: Mingwei Zhang <mizhang@google.com>
Signed-off-by: Mingwei Zhang <mizhang@google.com>
[sean: extract to separate patch, write changelog]
Reviewed-by: Sandipan Das <sandipan.das@amd.com>
Tested-by: Xudong Hao <xudong.hao@intel.com>
Tested-by: Manali Shukla <manali.shukla@amd.com>
Link: https://patch.msgid.link/20251206001720.468579-19-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>