staging: rtl8192e: Refactor tmp_ofdm_index variable assignment

Refactor tmp_ofdm_index variable assignment to avoid multiple
assignments which is not accepted by checkpatch.
Signed-off-by: Yogesh Hegde <yogi.kernel@gmail.com>
Tested-by: Philipp Hortmann <philipp.g.hortmann@gmail.com>
Link: https://lore.kernel.org/r/af7bc22ec142c33cf7346c1ab13d192b55095d1e.1683730854.git.yogi.kernel@gmail.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/rtl8192e/rtl8192e/rtl_dm.c

@@ -689,8 +689,8 @@ static void _rtl92e_dm_tx_power_tracking_cb_thermal(struct net_device *dev)
 	priv->thermal_meter[1] = ThermalMeterVal;
 
 	if (priv->thermal_meter[0] >= (u8)tmp_reg) {
-		tmp_ofdm_index = tmp_cck_20m_index = 6+(priv->thermal_meter[0] -
-			      (u8)tmp_reg);
+		tmp_ofdm_index = 6 + (priv->thermal_meter[0] - (u8)tmp_reg);
+		tmp_cck_20m_index = tmp_ofdm_index;
 		tmp_cck_40m_index = tmp_cck_20m_index - 6;
 		if (tmp_ofdm_index >= OFDM_TABLE_LEN)
 			tmp_ofdm_index = OFDM_TABLE_LEN - 1;