mmc: tmio_mmc: fix card eject during IO with DMA

When DMA is in use and the card is ejected during IO, DMA transfers have to
be terminated, otherwise the dmaengine driver fails to operate properly,
when the card is re-inserted.

Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: Chris Ball <cjb@laptop.org>