[PATCH] type-safe min() in prism54

we do min() on u8 and small integer constant; cast the latter to u8.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

drivers/net/wireless/prism54/isl_ioctl.c

@@ -748,7 +748,7 @@ prism54_get_essid(struct net_device *ndev, struct iw_request_info *info,
 	if (essid->length) {
 		dwrq->flags = 1;	/* set ESSID to ON for Wireless Extensions */
 		/* if it is to big, trunk it */
-		dwrq->length = min(IW_ESSID_MAX_SIZE, essid->length);
+		dwrq->length = min((u8)IW_ESSID_MAX_SIZE, essid->length);
 	} else {
 		dwrq->flags = 0;
 		dwrq->length = 0;