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>
diff --git a/arch/x86/xen/xen-asm_64.S b/arch/x86/xen/xen-asm_64.S
index 7f58304..3b9bda4 100644
--- a/arch/x86/xen/xen-asm_64.S
+++ b/arch/x86/xen/xen-asm_64.S
@@ -122,7 +122,7 @@
 	push %r9
 	push %r10
 	push %r11
-	call force_evtchn_callback
+	call xen_force_evtchn_callback
 	pop %r11
 	pop %r10
 	pop %r9