improve mworm mcat error message

Reference: /n/atom/patch/applied/fsmwormmsg
Date: Sat Apr 19 14:43:20 CES 2014
Signed-off-by: quanstro@quanstro.net

--- /sys/src/fs/dev/mworm.c	Sat Apr 19 14:43:17 2014
+++ /sys/src/fs/dev/mworm.c	Sat Apr 19 14:43:18 2014
@@ -66,7 +66,7 @@
 			return devread(x, b-l, c);
 		l += m;
 	}
-	print("mcatread %lld %lld\n", (Wideoff)b, (Wideoff)l);
+	print("mcatread %Z %lld %lld\n", d, (Wideoff)b, (Wideoff)l);
 	return 1;
 }
 
@@ -87,7 +87,7 @@
 			return devwrite(x, b-l, c);
 		l += m;
 	}
-	print("mcatwrite %lld %lld\n", (Wideoff)b, (Wideoff)l);
+	print("mcatwrite %Z %lld %lld\n", d, (Wideoff)b, (Wideoff)l);
 	return 1;
 }