Bluetooth: controller: Add option to enable conn. CTE request feature

Add Kconfig option that enables BT v5.1 Connection CTE request feature.

Signed-off-by: Piotr Pryga <piotr.pryga@nordicsemi.no>
diff --git a/subsys/bluetooth/controller/Kconfig.df b/subsys/bluetooth/controller/Kconfig.df
index 4e161da..5e7f52a 100644
--- a/subsys/bluetooth/controller/Kconfig.df
+++ b/subsys/bluetooth/controller/Kconfig.df
@@ -89,6 +89,13 @@
 	help
 	  Enable support for reception of Constant Tone Extension in controller.
 
+config BT_CTLR_DF_CONN_CTE_REQ
+	bool "Enable Connection CTE Request feature"
+	depends on BT_CTLR_DF_CTE_RX && BT_CONN
+	help
+	  Enable support for Bluetooth v5.1 Connection CTE Request feature
+	  in controller.
+
 config BT_CTLR_DF_CONN_CTE_RSP
 	bool "Enable Connection CTE Response feature"
 	depends on BT_CTLR_DF_CTE_TX && BT_CONN