arm64: dts: qcom: sc7280-idp: 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/1650556567-4995-2-git-send-email-quic_vnivarth@quicinc.com

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

@@ -408,10 +408,13 @@ &qup_uart5_rx {
 
 &qup_uart7_cts {
 	/*
-	 * 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;
 };
 
 &qup_uart7_rts {
@@ -503,10 +506,13 @@ 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;
 	};
 
 	qup_uart7_sleep_rts: qup-uart7-sleep-rts {