board.SPI().try_lock() is not freed over soft-reset

```
Adafruit CircuitPython 6.0.0-alpha.2-190-g817a52228 on 2020-08-11; Particle Xenon with nRF52840
>>> import board
>>> board.SPI().try_lock()
True
>>> 
soft reboot
...
Adafruit CircuitPython 6.0.0-alpha.2-190-g817a52228 on 2020-08-11; Particle Xenon with nRF52840
>>> import board
>>> board.SPI().try_lock()
False
```