If a read or write operation encounters an error, the card
might stay in "recv" or "data" state, and never get back to
"tran" state.
In these cases, the host is required to send a CMD12 (end
transmission) to switch the FSM of the card back to "tran"
state, as described in MMC Specification, chapter "Data
Transfer Mode".
Signed-off-by: Robert Jarzmik <robert.jarzmik@free.fr>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>