KVM: selftests: Extend {kvm,this}_pmu_has() to support fixed counters

KVM: selftests: Extend {kvm,this}_pmu_has() to support fixed counters

Extend the kvm_x86_pmu_feature framework to allow querying for fixed
counters via {kvm,this}_pmu_has().  Like architectural events, checking
for a fixed counter annoyingly requires checking multiple CPUID fields, as
a fixed counter exists if:

  FxCtr[i]_is_supported := ECX[i] || (EDX[4:0] > i);

Note, KVM currently doesn't actually support exposing fixed counters via
the bitmask, but that will hopefully change sooner than later, and Intel's
SDM explicitly "recommends" checking both the number of counters and the
mask.

Rename the intermedate "anti_feature" field to simply 'f' since the fixed
counter bitmask (thankfully) doesn't have reversed polarity like the
architectural events bitmask.

Note, ideally the helpers would use BUILD_BUG_ON() to assert on the
incoming register, but the expected usage in PMU tests can't guarantee the
inputs are compile-time constants.

Opportunistically define macros for all of the known architectural events
and fixed counters.

Tested-by: Dapeng Mi <dapeng1.mi@linux.intel.com>
Link: https://lore.kernel.org/r/20240109230250.424295-15-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>