rp2/mpbthciport: Fix HCI UART config.

Fixes are:
- The baudrate argument is a keyword arg, it was passed before as a
  positional arg.
- Use the port and baudrate arguments passed from higher level code instead
  of the hard-coded port ID and baudrate, which would allow HCI drivers to
  change baudrates.
- Increase UART char timeout and RX buffer size.
Signed-off-by: iabdalkader <i.abdalkader@gmail.com>

ports/rp2/mpbthciport.c

@@ -87,16 +87,18 @@ int mp_bluetooth_hci_uart_init(uint32_t port, uint32_t baudrate) {
     debug_printf("mp_bluetooth_hci_uart_init\n");
 
     mp_obj_t args[] = {
-        MP_OBJ_NEW_SMALL_INT(MICROPY_HW_BLE_UART_ID),
-        MP_OBJ_NEW_SMALL_INT(MICROPY_HW_BLE_UART_BAUDRATE),
+        MP_OBJ_NEW_SMALL_INT(port),
+        MP_OBJ_NEW_QSTR(MP_QSTR_baudrate), MP_OBJ_NEW_SMALL_INT(baudrate),
         MP_OBJ_NEW_QSTR(MP_QSTR_flow), MP_OBJ_NEW_SMALL_INT((1 | 2)),
         MP_OBJ_NEW_QSTR(MP_QSTR_timeout), MP_OBJ_NEW_SMALL_INT(1000),
+        MP_OBJ_NEW_QSTR(MP_QSTR_timeout_char), MP_OBJ_NEW_SMALL_INT(200),
+        MP_OBJ_NEW_QSTR(MP_QSTR_rxbuf), MP_OBJ_NEW_SMALL_INT(768),
     };
 
     // This is a statically-allocated UART (see machine_uart.c), and doesn't
     // contain any heap pointers other than the ringbufs (which are already
     // root pointers), so no need to track this as a root pointer.
-    mp_bthci_uart = MP_OBJ_TYPE_GET_SLOT(&machine_uart_type, make_new)((mp_obj_t)&machine_uart_type, 2, 2, args);
+    mp_bthci_uart = MP_OBJ_TYPE_GET_SLOT(&machine_uart_type, make_new)((mp_obj_t)&machine_uart_type, 1, 5, args);
 
     // Start the HCI polling to process any initial events/packets.
     mp_bluetooth_hci_start_polling();