Time outs can be expected, e.g. when probing whether a card is a MMC
one. The core handles it, so don't have the driver print an error.

While at it, simplify the error handling. We don't need to read the
status more than once and returning -EPERM on non-timeout is what the
other drivers are doing.

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