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 <[e-mail]>
Tested-by: Martín Ernesto Barreyro <[e-mail]>
Cc: Stable <[e-mail]>
Signed-off-by: John W. Linville <[e-mail]>

drivers/net/wireless/rtl818x/rtl8187_rtl8225.c

···
 	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);
···
 	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);