KVM: selftests: Update gitignore file for latest changes

The kvm_create_max_vcpus test has been moved to the main directory,
and sync_regs_test is now available on s390x, too.
Signed-off-by: NThomas Huth <thuth@redhat.com>
Acked-by: NShuah Khan <skhan@linuxfoundation.org>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

tools/testing/selftests/kvm/.gitignore

+/s390x/sync_regs_test
 /x86_64/cr4_cpuid_sync_test
 /x86_64/evmcs_test
 /x86_64/hyperv_cpuid
-/x86_64/kvm_create_max_vcpus
 /x86_64/mmio_warning_test
 /x86_64/platform_info_test
 /x86_64/set_sregs_test
@@ -13,3 +13,4 @@
 /x86_64/vmx_tsc_adjust_test
 /clear_dirty_log_test
 /dirty_log_test
+/kvm_create_max_vcpus