aarch64: Number of SMP CPUS exceeds max CPUs supported by machine (10 > 8) for M1 Pro/Max
Description of problem:
Trying to launch QEMU with more than 8 cores gives the following error:

`qemu-system-aarch64: Number of SMP CPUs requested (10) exceeds max CPUs supported by machine 'mach-virt' (8)`

Apple M1 Pro can have up to 10 cores while M1 Max only has 10 cores.
Steps to reproduce:
1. Install QEMU via homebrew (or MacPorts or from source)
2. Run `qemu-system-aarch64 -machine virt,highmem=off -accel hvf -cpu cortex-a72 -smp 10`
3. Get error, QEMU doesn't start