boot.py fails after soft reboot after running camera example

[sfe-SparkFro]

Looks like there's an issue with the SD card not mounting.

[sfe-SparkFro]

Looks like the camera DMA was still active from before the soft reset. The SPI bus uses the DMA for large transfers, so when the SD card tried to get mounted, it ended up waiting on the previous camera DMA transfer to finish.