[nrf fromtree] bluetooth: controller: Only BT_CTLR_ECDH default y if BT_HCI_RAW

In zephyrproject-rtos/zephyr#84268
the ability to use the controller for ECDH was removed from
the host.

This means that BT_CTLR_ECDH is now only useful when using
BT_HCI_RAW.

Signed-off-by: Sean Madigan <[email protected]>
(cherry picked from commit 706938d)

Author: sean-madigan

subsys/bluetooth/controller/Kconfig

@@ -512,7 +512,7 @@ config BT_CTLR_LE_ENC
 config BT_CTLR_ECDH
 	bool "Elliptic Curve Diffie-Hellman (ECDH)"
 	depends on BT_CTLR_ECDH_SUPPORT
-	default y
+	default y if BT_HCI_RAW
 	help
 	  Enable support for Bluetooth v4.2 Elliptic Curve Diffie-Hellman
 	  feature in the controller.