Set kcons index to -1 (i.e., acquire all device indexes).

This reverts part of the previous changeset, which prevented
console=tty0 from doing the obvious thing in a domU guest
(i.e., send output on the virtual console). This is because
the tty index ends up being 1.

I don't think setting the index to other than -1 really
buys us anything anyway. Any other driver that specifies
a name that conflicts with us will almost certainly set their
index to -1, so we cannot avoid conflicts by choosing a
more restrictive (singleton) value.

Signed-off-by: Keir Fraser <keir@xensource.com>

     1.1 --- a/linux-2.6-xen-sparse/drivers/xen/console/console.c	Tue Dec 13 22:05:18 2005 +0100
     1.2 +++ b/linux-2.6-xen-sparse/drivers/xen/console/console.c	Tue Dec 13 22:12:02 2005 +0100
     1.3 @@ -213,9 +213,6 @@ static int __init xen_console_init(void)
     1.4  		return __RETCODE;
     1.5  	}
     1.6  
     1.7 -	/* We only bind to one device index (-1 means all indexes). */
     1.8 -	kcons_info.index = xc_num;
     1.9 -
    1.10  	wbuf = alloc_bootmem(wbuf_size);
    1.11  
    1.12  	register_console(&kcons_info);