[IA64] vti fault handler clean up: improve the VTi domain fault handler

[IA64] vti fault handler clean up: improve the VTi domain fault handler

Improve the VTi domain fault handler panic path.  Currently when a
VTi fault handler finds something wrong, it enters an infinite loop
in vmx_panic with interrupts masked.  It makes sense if hw-based
debugger is available.  However in most cases this isn't available,
especially for normal users.  This patch makes those panic paths
more user friendly by printing out the panic message.  The old
behaviour is left with vmx_panic configuration.

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