IA64: fix emulation of fp emulation in pv domain

IA64: fix emulation of fp emulation in pv domain

This patch is a part of fixes to bug reported as
http://bugzilla.xensource.com/bugzilla/show_bug.cgi?id=1392

When vmm fails to get a bundle in a question during fpswa processing,
there is no way, but a guest provides the bundle.
On the other hand the current implementation just returns random value.
This patch make the fpswa hypercall calling convention complicated and
pass necessary informations to the hypervisor.

Signed-off-by: Isaku Yamahata <yamahata@valinux.co.jp>