kvm: selftests: aarch64: fix default vm mode

VM_MODE_P52V48_4K is not a valid mode for AArch64. Replace its
use in vm_create_default() with a mode that works and represents
a good AArch64 default. (We didn't ever see a problem with this
because we don't have any unit tests using vm_create_default(),
but it's good to get it fixed in advance.)
Reported-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Andrew Jones <drjones@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

tools/testing/selftests/kvm/lib/aarch64/processor.c

@@ -226,7 +226,7 @@ struct kvm_vm *vm_create_default(uint32_t vcpuid, uint64_t extra_mem_pages,
 	uint64_t extra_pg_pages = (extra_mem_pages / ptrs_per_4k_pte) * 2;
 	struct kvm_vm *vm;
 
-	vm = vm_create(VM_MODE_P52V48_4K, DEFAULT_GUEST_PHY_PAGES + extra_pg_pages, O_RDWR);
+	vm = vm_create(VM_MODE_P40V48_4K, DEFAULT_GUEST_PHY_PAGES + extra_pg_pages, O_RDWR);
 
 	kvm_vm_elf_load(vm, program_invocation_name, 0, 0);
 	vm_vcpu_add_default(vm, vcpuid, guest_code);