rtl8187: Fix error in setting OFDM power settings for RTL8187L

After reports of poor performance, a review of the latest vendor driver
(rtl8187_linux_26.1025.0328.2007) for RTL8187L devices was undertaken.

A difference was found in the code used to index the OFDM power tables. When
the Linux driver was changed, my unit works at a much greater range than
before. I think this fixes Bugzilla #12380 and has been tested by at least
two other users.
Signed-off-by: Larry Finger <Larry.Finger@lwfinger.net>
Tested-by: Martín Ernesto Barreyro <barreyromartin@gmail.com>
Cc: Stable <stable@kernel.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/rtl818x/rtl8187_rtl8225.c

@@ -285,7 +285,10 @@ static void rtl8225_rf_set_tx_power(struct ieee80211_hw *dev, int channel)
 	ofdm_power = priv->channels[channel - 1].hw_value >> 4;
 
 	cck_power = min(cck_power, (u8)11);
-	ofdm_power = min(ofdm_power, (u8)35);
+	if (ofdm_power > (u8)15)
+		ofdm_power = 25;
+	else
+		ofdm_power += 10;
 
 	rtl818x_iowrite8(priv, &priv->map->TX_GAIN_CCK,
 			 rtl8225_tx_gain_cck_ofdm[cck_power / 6] >> 1);
@@ -536,7 +539,10 @@ static void rtl8225z2_rf_set_tx_power(struct ieee80211_hw *dev, int channel)
 	cck_power += priv->txpwr_base & 0xF;
 	cck_power = min(cck_power, (u8)35);
 
-	ofdm_power = min(ofdm_power, (u8)15);
+	if (ofdm_power > (u8)15)
+		ofdm_power = 25;
+	else
+		ofdm_power += 10;
 	ofdm_power += priv->txpwr_base >> 4;
 	ofdm_power = min(ofdm_power, (u8)35);