mmc: atmel-mci: abort transfer on timeout error

commit c1fa3426aa5c782724c97394303d52228206eda4 upstream.

When a software timeout occurs, the transfer is not stopped. In DMA case,
it causes DMA channel to be stuck because the transfer is still active
causing following transfers to be queued but not computed.

Signed-off-by: Ludovic Desroches <ludovic.desroches@atmel.com>
Reported-by: Alexander Morozov <etesial@gmail.com>
Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: Chris Ball <cjb@laptop.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>