preinit: use grep -q where applicable

SVN-Revision: 19481

target/linux/ifxmips/nfs/base-files/lib/preinit/01_init_nfs_ifxmips

@@ -2,7 +2,7 @@
 
 
 init_nfs() {
-	grep "/dev/root" /proc/mounts |grep -q nfs && {
+	grep "/dev/root" /proc/mounts | grep -q nfs && {
 		echo "- init nfs -"
 		exec /sbin/init
 	}