make enough room to add tbdf to io allocation

Reference: /n/atom/patch/applied/archionamesz
Date: Mon May  5 21:46:22 CES 2014
Signed-off-by: quanstro@quanstro.net

--- /sys/src/nix/k10/devarch.c	Mon May  5 21:46:22 2014
+++ /sys/src/nix/k10/devarch.c	Mon May  5 21:46:22 2014
@@ -11,7 +11,7 @@
 struct IOMap
 {
 	IOMap	*next;
-	char	tag[13];
+	char	tag[16+1];
 	uint	start;
 	uint	end;
 };
@@ -285,7 +285,7 @@
 		for(map = iomap.map; n > 0 && map != nil; map = map->next){
 			if(offset-- > 0)
 				continue;
-			sprint(p, "%#8ux %#8ux %-12.12s\n", map->start, map->end-1, map->tag);
+			sprint(p, "%#8ux %#8ux %-16.16s\n", map->start, map->end-1, map->tag);
 			p += Linelen;
 			n--;
 		}