mwifiex: avoid out of bounds access in mwifiex_get_common_rates.

Check that the array indexes are in-bounds before accessing the rate2 and tmp
arrays.

Found with the following semantic patch:

<smpl>
@@
identifier t;
identifier idx;
expression E;
statement S;
@@
* for (... ; <+... t[idx] ...+> && idx < E ; ...)
S
</smpl>

Signed-off-by: Cyril Roelandt <tipecaml@gmail.com>
Acked-by: Bing Zhao <bzhao@marvell.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/mwifiex/join.c

@@ -157,8 +157,8 @@ static int mwifiex_get_common_rates(struct mwifiex_private *priv, u8 *rate1,
 
 	memset(rate1, 0, rate1_size);
 
-	for (i = 0; rate2[i] && i < rate2_size; i++) {
-		for (j = 0; tmp[j] && j < rate1_size; j++) {
+	for (i = 0; i < rate2_size && rate2[i]; i++) {
+		for (j = 0; j < rate1_size && tmp[j]; j++) {
 			/* Check common rate, excluding the bit for
 			   basic rate */
 			if ((rate2[i] & 0x7F) == (tmp[j] & 0x7F)) {