remove sprint

Reference: /n/atom/patch/applied/myethersprint
Date: Sat May  3 06:11:02 CES 2014
Signed-off-by: quanstro@quanstro.net

--- /sys/src/libip/myetheraddr.c	Sat May  3 06:10:56 2014
+++ /sys/src/libip/myetheraddr.c	Sat May  3 06:10:57 2014
@@ -9,15 +9,15 @@
 	char buf[256];
 
 	if(*dev == '/')
-		sprint(buf, "%s/addr", dev);
+		snprint(buf, sizeof buf, "%s/addr", dev);
 	else
-		sprint(buf, "/net/%s/addr", dev);
+		snprint(buf, sizeof buf, "/net/%s/addr", dev);
 
 	fd = open(buf, OREAD);
 	if(fd < 0)
 		return -1;
 
-	n = read(fd, buf, sizeof buf -1 );
+	n = read(fd, buf, sizeof buf -1);
 	close(fd);
 	if(n <= 0)
 		return -1;