preinit: use grep -q where applicable

SVN-Revision: 19482

target/linux/atheros/base-files/lib/preinit/15_preinit_iface_atheros

@@ -3,7 +3,7 @@
 # reset button only supported on ar5315+ at the moment
 preinit_ip() {
 	if [ -z "$pi_ifname" ]; then
-		grep 'Atheros AR231[567]' /proc/cpuinfo > /dev/null && {
+		grep -q 'Atheros AR231[567]' /proc/cpuinfo && {
 			if [ -e "/sys/bus/mdio_bus/drivers/Infineon ADM6996/0:00" -o \
 			     -e "/sys/bus/mdio_bus/drivers/Marvell 88E6060/0:10" ]; then
 				vconfig set_name_type DEV_PLUS_VID_NO_PAD
@@ -16,7 +16,7 @@ preinit_ip() {
 			pi_ifname=$ifname
 		}
 	fi
-	[ -n "$pi_ifname" ] && grep "$pi_ifname" /proc/net/dev >/dev/null && {
+	[ -n "$pi_ifname" ] && grep -q "$pi_ifname" /proc/net/dev && {
 		ifconfig $pi_ifname $pi_ip netmask $pi_netmask broadcast $pi_broadcast up
     	}
 }