kvm: selftests: conditionally build vm_xsave_req_perm()

vm_xsave_req_perm() is currently defined and used by x86_64 only.
Make it compiled into vm_create_with_vcpus() only when on x86_64
machines. Otherwise, it would cause linkage errors, e.g. on s390x.

Fixes: 415a3c33 ("kvm: selftests: Add support for KVM_CAP_XSAVE2")
Reported-by: Janis Schoetterl-Glausch <scgl@linux.ibm.com>
Signed-off-by: Wei Wang <wei.w.wang@intel.com>
Tested-by: Janis Schoetterl-Glausch <scgl@linux.ibm.com>
Message-Id: <20220118014817.30910-1-wei.w.wang@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

tools/testing/selftests/kvm/lib/kvm_util.c

@@ -393,10 +393,12 @@ struct kvm_vm *vm_create_with_vcpus(enum vm_guest_mode mode, uint32_t nr_vcpus,
 	struct kvm_vm *vm;
 	int i;
 
+#ifdef __x86_64__
 	/*
 	 * Permission needs to be requested before KVM_SET_CPUID2.
 	 */
 	vm_xsave_req_perm();
+#endif
 
 	/* Force slot0 memory size not small than DEFAULT_GUEST_PHY_PAGES */
 	if (slot0_mem_pages < DEFAULT_GUEST_PHY_PAGES)