mmc_spi: don't use EINVAL for possible transmission errors

This patch changes the reported error code for the responses
to a command from EINVAL to EFAULT/ENOSYS, as EINVAL is reserved
for non-recoverable host errors, and the responses from
the SD/MMC card may be because of recoverable transmission
errors in the command or in the response. Response codes
in SPI mode are NOT protected by a checksum, so don't trust them.

Signed-off-by: Wolfgang Muees <wolfgang.mues@auerswald.de>
Acked-by: Matt Fleming <matt@console-pimps.org>
Signed-off-by: Pierre Ossman <pierre@ossman.eu>