Tokenize() needs nelem(args) not sizeof args.

Reference: /n/sources/patch/applied/hub-tokenize
Date: Wed Jul 30 14:56:11 CES 2008
Signed-off-by: djeannot24@gmail.com

--- /sys/src/cmd/usb/usbd/hub.c	Wed Jul 30 14:55:14 2008
+++ /sys/src/cmd/usb/usbd/hub.c	Wed Jul 30 14:55:11 2008
@@ -199,7 +199,7 @@
 			if(qe == nil)
 				sysfatal("usbd: port %H.%d not found", h, port);
 			*qe = '\0';
-			nf = tokenize(q, field, sizeof field);
+			nf = tokenize(q, field, nelem(field));
 			if(nf < 2)
 				sysfatal("Ill-formed port status: %s", q);
 			if(strtol(field[0], nil, 0) == port)