[IA64] Failure to resume after INIT in user space

The OS INIT handler is loading incorrect values into cr.ifa on exit.
This shows up as a hang when resuming after an INIT that is delivered
while a cpu is in user space.  Correct the value loaded into cr.ifa.

Signed-off-by: Keith Owens <kaos@sgi.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>