IA64: fix fp fault/trap handler.

IA64: fix fp fault/trap handler.

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

When fpswa handler fails to get a bundle in guest,
fp fault/trap should be injected into the guest and let a guest
to handle it.
When the fpswa library return a error, there is no way to
pass the value to the guest. In that case, just inject fpswa
fault/trap into a guest running a risk that guest may get
error with their own fpswa call. Here it is assumed that
no applications depend on SIGFP process signal to recover
their computation.

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