perf/x86: Refuse to export capabilities for hybrid PMUs

Now that KVM disables vPMU support on hybrid CPUs, WARN and return zeros
if perf_get_x86_pmu_capability() is invoked on a hybrid CPU.  The helper
doesn't provide an accurate accounting of the PMU capabilities for hybrid
CPUs and needs to be enhanced if KVM, or anything else outside of perf,
wants to act on the PMU capabilities.

Cc: stable@vger.kernel.org
Cc: Andrew Cooper <Andrew.Cooper3@citrix.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Link: https://lore.kernel.org/all/20220818181530.2355034-1-kan.liang@linux.intel.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20230208204230.1360502-3-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>