mmc: tegra: SDMMC pads auto-calibration

Program initial drive code offsets which will be used by auto
calibration process.

Program fixed drive strengths for SDMMC pads in pad control
register when auto cal timeouts.
Fixed settings are based on Pre-SI analysis of the pad design.

Signed-off-by: Sowjanya Komatineni <skomatineni@nvidia.com>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>