arm: dts: axxia: the unit-address of cpu4 should match the reg value

commit f6da9000

 from
git://git.yoctoproject.org/linux-yocto v5.10/standard/sdkv5.10/axxia

The unit-address of cpu4 wasn't changed to match the reg value along
with other cpus. This patch is to fix this.

Reported-by: Mikael Beckius <mikael.beckius@windriver.com>
Signed-off-by: Quanyang Wang <quanyang.wang@windriver.com>
Signed-off-by: Bruce Ashfield <bruce.ashfield@gmail.com>
Signed-off-by: Liwei Song <liwei.song@windriver.com>