arm64: dts: qcom: sc7280-qcard: Configure CTS pin to bias-bus-hold for bluetooth

WLAN rail was leaking power during RBSC/sleep even after turning BT off.
Change active and sleep pinctrl configurations to handle same.
Signed-off-by: Vijaya Krishna Nivarthi <quic_vnivarth@quicinc.com>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Link: https://lore.kernel.org/r/1650556567-4995-3-git-send-email-quic_vnivarth@quicinc.com

arch/arm64/boot/dts/qcom/sc7280-qcard.dtsi

@@ -398,8 +398,14 @@ &qup_i2c13_data_clk {
 
 /* For mos_bt_uart */
 &qup_uart7_cts {
-	/* Configure a pull-down on CTS to match the pull of the Bluetooth module. */
-	bias-pull-down;
+	/*
+	 * Configure a bias-bus-hold on CTS to lower power
+	 * usage when Bluetooth is turned off. Bus hold will
+	 * maintain a low power state regardless of whether
+	 * the Bluetooth module drives the pin in either
+	 * direction or leaves the pin fully unpowered.
+	 */
+	bias-bus-hold;
 };
 
 /* For mos_bt_uart */
@@ -490,10 +496,13 @@ qup_uart7_sleep_cts: qup-uart7-sleep-cts {
 		pins = "gpio28";
 		function = "gpio";
 		/*
-		 * Configure a pull-down on CTS to match the pull of
-		 * the Bluetooth module.
+		 * Configure a bias-bus-hold on CTS to lower power
+		 * usage when Bluetooth is turned off. Bus hold will
+		 * maintain a low power state regardless of whether
+		 * the Bluetooth module drives the pin in either
+		 * direction or leaves the pin fully unpowered.
 		 */
-		bias-pull-down;
+		bias-bus-hold;
 	};
 
 	/* For mos_bt_uart */