staging: rt2860: off by one errors

The code is trying to say that if the offset is higher than the max it
should be set to the max, but there is an off by one bug and it sets it
one passed the end of the array.
Signed-off-by: Dan Carpenter <error27@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/staging/rt2860/sta_ioctl.c

@@ -1047,8 +1047,7 @@ int rt_ioctl_giwscan(struct net_device *dev,
 			if (tmpRate == 0x6c
 			    && pAdapter->ScanTab.BssEntry[i].HtCapabilityLen >
 			    0) {
-				int rate_count =
-				    sizeof(ralinkrate) / sizeof(__s32);
+				int rate_count = ARRAY_SIZE(ralinkrate);
 				struct rt_ht_cap_info capInfo =
 				    pAdapter->ScanTab.BssEntry[i].HtCapability.
 				    HtCapInfo;
@@ -1061,10 +1060,11 @@ int rt_ioctl_giwscan(struct net_device *dev,
 				int rate_index =
 				    12 + ((u8)capInfo.ChannelWidth * 24) +
 				    ((u8)shortGI * 48) + ((u8)maxMCS);
+
 				if (rate_index < 0)
 					rate_index = 0;
-				if (rate_index > rate_count)
-					rate_index = rate_count;
+				if (rate_index >= rate_count)
+					rate_index = rate_count - 1;
 				iwe.u.bitrate.value =
 				    ralinkrate[rate_index] * 500000;
 			}
@@ -2338,7 +2338,7 @@ int rt_ioctl_giwrate(struct net_device *dev,
 */
 	GET_PAD_FROM_NET_DEV(pAd, dev);
 
-	rate_count = sizeof(ralinkrate) / sizeof(__s32);
+	rate_count = ARRAY_SIZE(ralinkrate);
 	/*check if the interface is down */
 	if (!RTMP_TEST_FLAG(pAd, fRTMP_ADAPTER_INTERRUPT_IN_USE)) {
 		DBGPRINT(RT_DEBUG_TRACE, ("INFO::Network is down!\n"));
@@ -2369,8 +2369,8 @@ int rt_ioctl_giwrate(struct net_device *dev,
 	if (rate_index < 0)
 		rate_index = 0;
 
-	if (rate_index > rate_count)
-		rate_index = rate_count;
+	if (rate_index >= rate_count)
+		rate_index = rate_count - 1;
 
 	wrqu->bitrate.value = ralinkrate[rate_index] * 500000;
 	wrqu->bitrate.disabled = 0;