pc: Create pc-*-1.6 machine-types

Some CPU model fixes are going to be included and they will require
compatibility properties in the pc-*-1.5 machine-types.

Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
Reviewed-by: Igor Mammedov <imammedo@redhat.com>
Signed-off-by: Andreas Färber <afaerber@suse.de>
target-i386: Update model values on Conroe/Penryn/Nehalem CPU models

The CPUID model values on Conroe, Penryn, and Nehalem are too
conservative and don't reflect the values found on real Conroe, Penryn,
and Nehalem CPUs.

This causes at least one known problems: Windows XP disables sysenter
when (family == 6 && model <= 2), but Skype tries to use the sysenter
instruction anyway because it is reported as available on CPUID, making
it crash.

This patch sets appropriate model values that correspond to real Conroe,
Penryn, and Nehalem CPUs.

Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
Reviewed-by: Igor Mammedov <imammedo@redhat.com>
Signed-off-by: Andreas Färber <afaerber@suse.de>
target-i386: Set level=4 on Conroe/Penryn/Nehalem

The CPUID level value on Conroe, Penryn, and Nehalem are too low. This
causes at least one known problem: the -smp "threads" option doesn't
work as expect if level is < 4, because thread count information is
provided to the guest on CPUID[EAX=4,ECX=2].EAX

Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
Reviewed-by: Igor Mammedov <imammedo@redhat.com>
Signed-off-by: Andreas Färber <afaerber@suse.de>