xen: compile irq functions without -pg for ftrace

For some reason I managed to miss a bunch of irq-related functions
which also need to be compiled without -pg when using ftrace.  This
patch moves them into their own file, and starts a cleanup process
I've been meaning to do anyway.

Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: "Alex Nixon (Intern)" <Alex.Nixon@eu.citrix.com>
Cc: Eduardo Habkost <ehabkost@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

arch/x86/xen/xen-ops.h

@@ -31,6 +31,7 @@ void xen_vcpu_restore(void);
 
 void __init xen_build_dynamic_phys_to_machine(void);
 
+void xen_init_irq_ops(void);
 void xen_setup_timer(int cpu);
 void xen_setup_cpu_clockevents(void);
 unsigned long xen_tsc_khz(void);