mmc: sdhci-msm: Convert to mmc_send_tuning()

Instead of having a local hack taking care of sending the tuning
command and as well to verify the response pattern, let's convert to
the common mmc_send_tuning() API instead.

Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Tested-by: Georgi Djakov <gdjakov@mm-sol.com>
Acked-by: Georgi Djakov <gdjakov@mm-sol.com>
Reviewed-by: Stephen Boyd <sboyd@codeaurora.org>