extmod/btstack: Use MICROPY_HW_BLE_UART_BAUDRATE for first UART init.
extmod/btstack: Use MICROPY_HW_BLE_UART_BAUDRATE for first UART init.

Otherwise the UART may be left in a state at baudrate=0.

Signed-off-by: Damien George <99e6b749acbfbe2a596df99e91d24d6e1fdbee00@micropython.org>

bvernoux/micropython,bvernoux/micropython,adafruit/circuitpython,adafruit/circuitpython,adafruit/circuitpython,henriknelson/micropython,bvernoux/micropython,henriknelson/micropython,adafruit/circuitpython,henriknelson/micropython,henriknelson/micropython,bvernoux/micropython,henriknelson/micropython,adafruit/circuitpython,bvernoux/micropython,adafruit/circuitpython