The interrupt driven card detect logic was enabled
but the auto mounter was not. That interrupt was
calling mmcsd_mediachange.
There is a reentrancy issues in the kinetis callback logic.
Toplevel calls mmcsd_mediachange calls SDIO_CALLBACKENABLE
that calls kinetis_callbackenable that calls kinetis_callback
that calls mmcsd_mediachange.
David Sidrane