iwlwifi: fix some warnings

This fixes all kinds of warnings in iwlwifi.

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/iwlwifi/iwl-4965.h b/drivers/net/wireless/iwlwifi/iwl-4965.h
index c8e7028..0ec217d 100644
--- a/drivers/net/wireless/iwlwifi/iwl-4965.h
+++ b/drivers/net/wireless/iwlwifi/iwl-4965.h
@@ -294,8 +294,8 @@
 
 #define SEQ_TO_QUEUE(x)  ((x >> 8) & 0xbf)
 #define QUEUE_TO_SEQ(x)  ((x & 0xbf) << 8)
-#define SEQ_TO_INDEX(x) (x & 0xff)
-#define INDEX_TO_SEQ(x) (x & 0xff)
+#define SEQ_TO_INDEX(x) ((u8)(x & 0xff))
+#define INDEX_TO_SEQ(x) ((u8)(x & 0xff))
 #define SEQ_HUGE_FRAME  (0x4000)
 #define SEQ_RX_FRAME    __constant_cpu_to_le16(0x8000)
 #define SEQ_TO_SN(seq) (((seq) & IEEE80211_SCTL_SEQ) >> 4)