I originally had just changed the NEWINTF ioctl to send over 48-bits of
information, which works on 64-bit but not on 32-bit (since the arg is an
unsigned long).  Additionally, the previous changes would break an older
userland against a new kernel.  For that reason, introduce a new ioctl
(NEWINTF_EXT) that fixes both of these problems.  This is the dom0 userland side.

Signed-off-by: Chris Lalancette <clalance@redhat.com>