cpu defs: use Intel flag names for Intel models (v2)

cpu defs: use Intel flag names for Intel models (v2)

Use 'i64' instead of 'lm' and 'xd' instead of 'nx' on Intel models.

The flags have different names on Intel docs, so use those names for clarity.

This is based on a previous patch from John Cooper where this was introduced
with many other changes at the same time. Original John's patch submission is
at Message-ID: <4DDAD5E7.2020002@redhat.com>, <http://marc.info/?l=qemu-devel&m=130618871926030>.

Changes v1 -> v2:
 - Rebase patch against latest Qemu git tree

Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>