rtlwifi: rtl818x: remove redundant check for cck_power > 15

cck_poweri cannot be greated than 15 as is derived from the bottom 4 bits
from riv->channels[channel - 1].hw_value & 0xf.  Hence the check for it
being greater than 15 is redundant and can be removed.

Detected by CoverityScan, CID#744303 ("Logically dead code")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>

drivers/net/wireless/realtek/rtl818x/rtl8187/rtl8225.c

@@ -688,9 +688,6 @@ static void rtl8225z2_b_rf_set_tx_power(struct ieee80211_hw *dev, int channel)
 	cck_power = priv->channels[channel - 1].hw_value & 0xF;
 	ofdm_power = priv->channels[channel - 1].hw_value >> 4;
 
-	if (cck_power > 15)
-		cck_power = (priv->hw_rev == RTL8187BvB) ? 15 : 22;
-	else
 	cck_power += (priv->hw_rev == RTL8187BvB) ? 0 : 7;
 	cck_power += priv->txpwr_base & 0xF;
 	cck_power = min(cck_power, (u8)35);