[wireless ipw2100] kill unused-var warnings for debug-disabled code

drivers/net/wireless/ipw2100.c

@@ -3748,6 +3748,8 @@ static ssize_t store_memory(struct device *d, struct device_attribute *attr,
 	struct net_device *dev = priv->net_dev;
 	const char *p = buf;
 
+	(void) dev; /* kill unused-var warning for debug-only code */
+
 	if (count < 1)
 		return count;
 
@@ -4066,6 +4068,8 @@ static ssize_t store_scan_age(struct device *d, struct device_attribute *attr,
 	unsigned long val;
 	char *p = buffer;
 
+	(void) dev; /* kill unused-var warning for debug-only code */
+
 	IPW_DEBUG_INFO("enter\n");
 
 	strncpy(buffer, buf, len);