rtlwifi: rtl8723be: Remove set but unused variable 'cck_highpwr'

Fixes the following W=1 kernel build warning(s):

 drivers/net/wireless/realtek/rtlwifi/rtl8723be/trx.c: In function ‘_rtl8723be_query_rxphystatus’:
 drivers/net/wireless/realtek/rtlwifi/rtl8723be/trx.c:53:6: warning: variable ‘cck_highpwr’ set but not used [-Wunused-but-set-variable]

Cc: Ping-Ke Shih <pkshih@realtek.com>
Cc: Kalle Valo <kvalo@codeaurora.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: linux-wireless@vger.kernel.org
Cc: netdev@vger.kernel.org
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/20201102112410.1049272-33-lee.jones@linaro.org

drivers/net/wireless/realtek/rtlwifi/rtl8723be/trx.c

@@ -50,7 +50,6 @@ static void _rtl8723be_query_rxphystatus(struct ieee80211_hw *hw,
 	pstatus->rx_mimo_signalquality[1] = -1;
 
 	if (is_cck) {
-		u8 cck_highpwr;
 		u8 cck_agc_rpt;
 
 		cck_agc_rpt = p_phystrpt->cck_agc_rpt_ofdm_cfosho_a;
@@ -59,8 +58,7 @@ static void _rtl8723be_query_rxphystatus(struct ieee80211_hw *hw,
 		/* (2)PWDB, Average PWDB cacluated by
 		 * hardware (for rate adaptive)
 		 */
-		cck_highpwr = (u8)rtl_get_bbreg(hw, RFPGA0_XA_HSSIPARAMETER2,
-						 BIT(9));
+		rtl_get_bbreg(hw, RFPGA0_XA_HSSIPARAMETER2, BIT(9));
 
 		lan_idx = ((cck_agc_rpt & 0xE0) >> 5);
 		vga_idx = (cck_agc_rpt & 0x1f);