correct out-of-bounds references in funct.c

Reference: /n/sources/patch/applied/cc-funct-fsym-bounds
Date: Sun Mar  2 12:32:38 CET 2014
Signed-off-by: charles.forsyth@gmail.com

--- /sys/src/cmd/cc/funct.c	Sun Mar  2 12:32:18 2014
+++ /sys/src/cmd/cc/funct.c	Sun Mar  2 12:32:16 2014
@@ -238,7 +238,7 @@
 		goto bad;
 
 	f = alloc(sizeof(*f));
-	for(o=0; o<sizeof(f->sym); o++)
+	for(o=0; o<nelem(f->sym); o++)
 		f->sym[o] = S;
 
 	t->funct = f;