On the sama5d27, currently only the MCI used for boot is operational.
The other one errors out when failing to reset the card.

Changing the RESET_ALL to RESET_CMD | RESET_DATA fixes this.
This might be due to the SoC's "11.1   Software 'Reset For all'
command may not execute properly" erratum[1]:
> The software 'Reset For All' command may not execute properly, and, as
> a result, some registers of the host controller may not reset properly.
> The setting of the different registers must be checked beforere
> initializing the SD card.

[1]: DS80000827A

Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>