hvf: Split up hv_vm_create logic per arch

hvf: Split up hv_vm_create logic per arch

This is preliminary work to split up hv_vm_create
logic per platform so we can support creating VMs
with > 64GB of RAM on Apple Silicon machines. This
is done via ARM HVF's hv_vm_config_create() (and
other APIs that modify this config that will be
coming in future patches). This should have no
behavioral difference at all as hv_vm_config_create()
just assigns the same default values as if you just
passed NULL to the function.

Signed-off-by: Danny Canter <danny_canter@apple.com>
Message-id: 20240828111552.93482-3-danny_canter@apple.com
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>