Bluetooth: controller: Enable Zephyr VS HCI in ULL/LLL impl.

Enable the support for Zephyr HCI Vendor-Specific Commands
and Event in the ULL/LLL split architecture implementation
of the controller.

Signed-off-by: Vinayak Kariappa Chettimada <vich@nordicsemi.no>

subsys/bluetooth/controller/Kconfig

@@ -42,6 +42,7 @@ endchoice
 config BT_LLL_VENDOR_NORDIC
 	bool "Use Nordic LLL"
 	depends on BT_LL_SW_SPLIT && SOC_COMPATIBLE_NRF
+	select BT_HAS_HCI_VS
 	select ENTROPY_NRF5_RNG
 	select ENTROPY_NRF5_BIAS_CORRECTION
 	default y