drm/virtio: Fix memory leak in virtio_gpu_object_create()

The virtio_gpu_object_shmem_init() will alloc memory and save it in
@ents, so when virtio_gpu_array_alloc() fails, this memory should be
freed, this patch fixes it.

Fixes: e7fef092 ("drm/virtio: Simplify error handling of virtio_gpu_object_create()")
Signed-off-by: Xiu Jianfeng <xiujianfeng@huawei.com>
Reviewed-by: Dmitry Osipenko <dmitry.osipenko@collabora.com>
Signed-off-by: Dmitry Osipenko <dmitry.osipenko@collabora.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20221109091905.55451-1-xiujianfeng@huawei.com