airo: fix test for FLAG_RADIO_DOWN

We should be doing a shift (1 << FLAG_RADIO_DOWN) here before testing the flag. As luck would have it, this test works almost correctly. The current code tests for FLAG_RADIO_OFF instead of FLAG_RADIO_DOWN.

#define FLAG_RADIO_OFF 0 /* User disabling of MAC */
#define FLAG_RADIO_DOWN 1 /* ifup/ifdown disabling of MAC */

---
I don't have this hardware. Please review carefully.

index 1c008c6..ddc061d 100644
@@ -1869,7 +1869,7 @@ static int readStatsRid(struct airo_info*ai, StatsRid *sr, int rid, int lock)
 
 static void try_auto_wep(struct airo_info *ai)
 {
-	if (auto_wep && !(ai->flags & FLAG_RADIO_DOWN)) {
+	if (auto_wep && !test_bit(FLAG_RADIO_DOWN, &ai->flags)) {
 		ai->expires = RUN_AT(3*HZ);
 		wake_up_interruptible(&ai->thr_wait);
 	}