Unmounting SD card on GRiSP 2 results in error

[eproxus]

When un-plugging the SD card the GRiSP 2 prints the following error to the terminal:

emerg: mmcsd_detach: FIXME

SD mounting and un-mounting should work so that files on the SD card can be updated on a running system.

[c-mauderer]

The libbsd currently doesn't support removal of an SD card. I had a look at that in the past for some other project and it would be a big change with a lot of effort. I don't think that we will find a quick solution for that.