selftests: kvm: fix state save/load on processors without XSAVE

state_test and smm_test are failing on older processors that do not
have xcr0.  This is because on those processor KVM does provide
support for KVM_GET/SET_XSAVE (to avoid having to rely on the older
KVM_GET/SET_FPU) but not for KVM_GET/SET_XCRS.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

tools/testing/selftests/kvm/lib/x86_64/processor.c

@@ -1060,9 +1060,11 @@ struct kvm_x86_state *vcpu_save_state(struct kvm_vm *vm, uint32_t vcpuid)
         TEST_ASSERT(r == 0, "Unexpected result from KVM_GET_XSAVE, r: %i",
                 r);
 
+	if (kvm_check_cap(KVM_CAP_XCRS)) {
 		r = ioctl(vcpu->fd, KVM_GET_XCRS, &state->xcrs);
 		TEST_ASSERT(r == 0, "Unexpected result from KVM_GET_XCRS, r: %i",
 			    r);
+	}
 
 	r = ioctl(vcpu->fd, KVM_GET_SREGS, &state->sregs);
         TEST_ASSERT(r == 0, "Unexpected result from KVM_GET_SREGS, r: %i",
@@ -1103,9 +1105,11 @@ void vcpu_load_state(struct kvm_vm *vm, uint32_t vcpuid, struct kvm_x86_state *s
         TEST_ASSERT(r == 0, "Unexpected result from KVM_SET_XSAVE, r: %i",
                 r);
 
+	if (kvm_check_cap(KVM_CAP_XCRS)) {
 		r = ioctl(vcpu->fd, KVM_SET_XCRS, &state->xcrs);
 		TEST_ASSERT(r == 0, "Unexpected result from KVM_SET_XCRS, r: %i",
 			    r);
+	}
 
 	r = ioctl(vcpu->fd, KVM_SET_SREGS, &state->sregs);
         TEST_ASSERT(r == 0, "Unexpected result from KVM_SET_SREGS, r: %i",