virtio-gpu-rutabaga: Add empty interface to fix arm64 crash

virtio-gpu-rutabaga: Add empty interface to fix arm64 crash

Add an empty element to the interfaces array, which is consistent with
the behavior of other devices in qemu and fixes the crash on arm64.

0  0x0000fffff5c18550 in  () at /usr/lib64/libc.so.6
1  0x0000fffff6c9cd6c in g_strdup () at /usr/lib64/libglib-2.0.so.0
2  0x0000aaaaab4945d8 in g_strdup_inline (str=<optimized out>) at /usr/include/glib-2.0/glib/gstrfuncs.h:321
3  type_new (info=info@entry=0xaaaaabc1b2c8 <virtio_gpu_rutabaga_pci_info>) at ../qom/object.c:133
4  0x0000aaaaab494f14 in type_register_internal (info=0xaaaaabc1b2c8 <virtio_gpu_rutabaga_pci_info>) at ../qom/object.c:143
5  type_register (info=0xaaaaabc1b2c8 <virtio_gpu_rutabaga_pci_info>) at ../qom/object.c:152
6  type_register_static (info=0xaaaaabc1b2c8 <virtio_gpu_rutabaga_pci_info>) at ../qom/object.c:157
7  type_register_static_array (infos=<optimized out>, nr_infos=<optimized out>) at ../qom/object.c:165
8  0x0000aaaaab6147e8 in module_call_init (type=type@entry=MODULE_INIT_QOM) at ../util/module.c:109
9  0x0000aaaaab10a0ec in qemu_init_subsystems () at ../system/runstate.c:817
10 0x0000aaaaab10d334 in qemu_init (argc=13, argv=0xfffffffff198) at ../system/vl.c:2760
11 0x0000aaaaaae4da6c in main (argc=<optimized out>, argv=<optimized out>) at ../system/main.c:47

Signed-off-by: Cong Liu <liucong2@kylinos.cn>
Reviewed-by: Gurchetan Singh <gurchetansingh@chromium.org>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <20231031012515.15504-1-liucong2@kylinos.cn>