busybox: Fix syntax error when installing S10mdev

Signed-off-by: Philippe Pepiot <phil@philpep.org>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>

package/busybox/busybox.mk

@@ -31,7 +31,7 @@ endif
 # If mdev will be used for device creation enable it and copy S10mdev to /etc/init.d
 ifeq ($(BR2_ROOTFS_DEVICE_CREATION_DYNAMIC_MDEV),y)
 define BUSYBOX_INSTALL_MDEV_SCRIPT
-	[ -f $(TARGET_DIR)/etc/init.d/S10mdev ] ||
+	[ -f $(TARGET_DIR)/etc/init.d/S10mdev ] || \
 		install -D -m 0755 package/busybox/S10mdev \
 			$(TARGET_DIR)/etc/init.d/S10mdev
 endef