Only execute tuning for sd and sdio devices that are using
SDR50 or SDR104.

Make sure clock is hold during tuning for sdio devices.
Signed-off-by: NFredrik Soderstedt <fredrik.soderstedt@stericsson.com>
Acked-by: NJohan Rudholm <jrudholm@gmail.com>
Acked-by: NUlf Hansson <ulf.hansson@linaro.org>
Signed-off-by: NChris Ball <cjb@laptop.org>