Add hardware tuning function instead of software tuning because O2/Bayhub
SD host controller support hardware tuning.
Signed-off-by: Nernest.zhang <ernest.zhang@bayhubtech.com>
Acked-by: NAdrian Hunter <adrian.hunter@intel.com>
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>