iwlwifi: fix searching for best rate in new search column

This patch fixes a bug in Rate Scaling. When moving from SISO to MIMO we
need to choose the lowest higher rate, instead of choosing the highest in MIMO.
No doing this can lead to a high packet loss in the highest rate in MIMO,
leading not to move MIMO although lower in MIMO could give a better TPT.
Signed-off-by: NGuy Cohen <guy.cohen@intel.com>
Signed-off-by: NEmmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: NZhu Yi <yi.zhu@intel.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

drivers/net/wireless/iwlwifi/iwl-agn-rs.c

@@ -436,7 +436,7 @@ static int rs_collect_tx_data(struct iwl_rate_scale_data *windows,
 		/* Shift bitmap by one frame (throw away oldest history),
 		 * OR in "1", and increment "success" if this
 		 * frame was successful. */
-		window->data <<= 1;;
+		window->data <<= 1;
 		if (successes > 0) {
 			window->success_counter++;
 			window->data |= 0x1;
@@ -1128,6 +1128,7 @@ static s32 rs_get_best_rate(struct iwl_priv *priv,
 
 			/* Higher rate not available, use the original */
 			} else {
+				new_rate = rate;
 				break;
 			}
 		}