rtlwifi: initialize local array and set value.

GCC 4.8 is spitting out uninitialized-variable warnings against
"drivers/net/wireless/rtlwifi/rtl8192de/dm.c".

drivers/net/wireless/rtlwifi/rtl8192de/dm.c:941:31:
error: 'ofdm_index_old[1]' may be used uninitialized in this
function [-Werror=maybe-uninitialized]
     rtlpriv->dm.ofdm_index[i] = ofdm_index_old[i];

This patch adds initialization to the variable and properly sets its value.
Signed-off-by: Yunlian Jiang <yunlian@google.com>
Acked-by: Larry Finger <Larry.Finger@lwfinger.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/rtlwifi/rtl8192de/dm.c

@@ -842,7 +842,7 @@ static void rtl92d_dm_txpower_tracking_callback_thermalmeter(
 	long val_y, ele_c = 0;
 	u8 ofdm_index[2];
 	s8 cck_index = 0;
-	u8 ofdm_index_old[2];
+	u8 ofdm_index_old[2] = {0, 0};
 	s8 cck_index_old = 0;
 	u8 index;
 	int i;