docs/system/devices/cxl.rst suggests qemu-system-aarch64 command lines which fail with "Property 'virt-8.2-machine.cxl' not found"
Description of problem:
When trying to run qemu-system-aarch64 with "-M virt,gic-version=3,cxl=on -m 4g,maxmem=8G,slots=8 -cpu max", get the following problem:
"qemu-system-aarch64: Property 'virt-8.2-machine.cxl' not found". Do I need to compile the QEMU with specific option?
Steps to reproduce:
1. Compile QEMU with "./config" "make -j6"
2. Compile Linux
```
#!/bin/bash

KERNEL_PATH=/users/LiuQun/linux/arch/arm64/boot/Image
DISK_IMG=/users/LiuQun/ARM_img/disk-image-22.04-server-arm64.img

./build/qemu-system-aarch64 \
-M virt,gic-version=3,cxl=on -m 4g,maxmem=8G,slots=8 -cpu max \
-bios /users/LiuQun/ARM_img/QEMU_EFI.fd \
-kernel $KERNEL_PATH \
-drive file=$DISK_IMG,format=raw,if=none,id=drive-sata0-0-0 \
-device virtio-blk-device,drive=drive-sata0-0-0 \
-append "console=ttyAMA0 root=/dev/vda1 rdinit=/init acpi=off" \
-object memory-backend-file,id=cxl-mem1,share=on,mem-path=cxl-window1,size=512M \
-object memory-backend-file,id=cxl-label1,share=on,mem-path=cxl-label1,size=1K \
-object memory-backend-file,id=cxl-label2,share=on,mem-path=cxl-label2,size=1K \
-device pxb-cxl,id=cxl.0,bus=pcie.0,bus_nr=52,uid=0,len-window-base=1,window-base[0]=0x4c00000000,memdev[0]=cxl-mem1 \
-device cxl-rp,id=rp0,bus=cxl.0,addr=0.0,chassis=0,slot=0,port=0 \
-device cxl-rp,id=rp1,bus=cxl.0,addr=1.0,chassis=0,slot=1,port=1 \
-device cxl-type3,bus=rp0,memdev=cxl-mem1,id=cxl-pmem0,size=256M,lsa=cxl-label1 \
-device cxl-type3,bus=rp1,memdev=cxl-mem1,id=cxl-pmem1,size=256M,lsa=cxl-label2 \
-nographic

```
Additional information:
The same problem happens with QEMU 8.1