Bluetooth: controller: Implement CSA #2 for SubEvents

Implement the functions required to calculate the SubEvent 1
and SubEvent n mapped channel indices.

Signed-off-by: Vinayak Kariappa Chettimada <[email protected]>

Author: cvinayak

subsys/bluetooth/controller/Kconfig

@@ -641,6 +641,11 @@ config BT_CTLR_ASSERT_HANDLER
 	  and will be invoked whenever the controller code encounters
 	  an unrecoverable error.
 
+config BT_CTLR_TEST
+	bool "Run in-system unit tests"
+	help
+	  Run in-system unit tests
+
 endif # BT_CTLR
 
 config BT_CTLR_DEBUG_PINS_CPUAPP