e500: Use cpu_index instead of vcpu_dt_id

e500: Use cpu_index instead of vcpu_dt_id

The e500 platform code uses the function ppc_get_vcpu_dt_id() to get
an id to put in its device tree.  Which seems like it makes sense, but
ppc_get_vcpu_dt_id() is actually badly named - it only differs from
cpu_index in cases where you're running on KVM HV and the host's
number of threads differs from the guests.  Since KVM HV only supports
PAPR, not e500, it doesn't make sense to use it here.

Simply use the cpu_index instead (which is 'i' in this context
because qemu_get_cpu(i) returns the cpu with cpu_index == i).

Signed-off-by: Sam Bobroff <sam.bobroff@au1.ibm.com>
Reviewed-by: Greg Kurz <groug@kaod.org>
[dwg: Rewrote commit message]
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>