xen: register runstate info for boot CPU early

printk timestamping uses sched_clock, which in turn relies on runstate
info under Xen.  So make sure we set it up before any printks can
be called.
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Cc: Stable Kernel <stable@kernel.org>

arch/x86/xen/enlighten.c

@@ -1181,6 +1181,8 @@ asmlinkage void __init xen_start_kernel(void)
 
 	xen_raw_console_write("about to get started...\n");
 
+	xen_setup_runstate_info(0);
+
 	/* Start the world */
 #ifdef CONFIG_X86_32
 	i386_start_kernel();