Bluetooth: Controller: Use LOW_LAT_ULL implementation for ISO support

Use BT_CTLR_LOW_LAT_ULL implementation for enqueing ISO Rx.

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

Author: cvinayak

samples/bluetooth/hci_ipc/nrf5340_cpunet_iso-bt_ll_sw_split.conf

@@ -75,6 +75,7 @@ CONFIG_BT_CTLR_ADV_DATA_BUF_MAX=6
 
 # Increase the below to receive interleaved advertising chains
 CONFIG_BT_CTLR_SCAN_AUX_SET=3
+CONFIG_BT_CTLR_LOW_LAT_ULL=y
 # CONFIG_BT_CTLR_SCAN_AUX_USE_CHAINS=y
 # CONFIG_BT_CTLR_SCAN_AUX_CHAIN_COUNT=1