KVM: arm64: Use symbolic names for the PMU versions

Instead of using a bunch of magic numbers, use the existing definitions
that have been added since 8673e02e ("arm64: perf: Add support
for ARMv8.5-PMU 64-bit counters")
Reviewed-by: Alexandru Elisei <alexandru.elisei@arm.com>
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>

arch/arm64/kvm/pmu-emul.c

@@ -23,11 +23,11 @@ static void kvm_pmu_stop_counter(struct kvm_vcpu *vcpu, struct kvm_pmc *pmc);
 static u32 kvm_pmu_event_mask(struct kvm *kvm)
 {
 	switch (kvm->arch.pmuver) {
-	case 1:			/* ARMv8.0 */
+	case ID_AA64DFR0_PMUVER_8_0:
 		return GENMASK(9, 0);
-	case 4:			/* ARMv8.1 */
-	case 5:			/* ARMv8.4 */
-	case 6:			/* ARMv8.5 */
+	case ID_AA64DFR0_PMUVER_8_1:
+	case ID_AA64DFR0_PMUVER_8_4:
+	case ID_AA64DFR0_PMUVER_8_5:
 		return GENMASK(15, 0);
 	default:		/* Shouldn't be here, just for sanity */
 		WARN_ONCE(1, "Unknown PMU version %d\n", kvm->arch.pmuver);