[nrf fromlist] Bluetooth: Controller: Allow 0 ISO TX/RX buffer count

Upstream PR: zephyrproject-rtos/zephyr#69382

There is no need to allocate TX/RX buffers when the device is an receiver/transmitter only.

Signed-off-by: Yuxuan Cai <[email protected]>

Author: yuxCai

subsys/bluetooth/Kconfig.iso

@@ -77,7 +77,7 @@ config BT_ISO_MAX_CHAN
 config BT_ISO_TX_BUF_COUNT
 	int "Number of Isochronous TX buffers"
 	default 1
-	range 1 255
+	range 0 255
 	help
 	  Number of buffers available for outgoing Isochronous channel SDUs.
 
@@ -107,7 +107,7 @@ config BT_ISO_TX_MTU
 config BT_ISO_RX_BUF_COUNT
 	int "Number of Isochronous RX buffers"
 	default 1
-	range 1 255
+	range 0 255
 	help
 	  Number of buffers available for incoming Isochronous channel SDUs.