mmc: sdhci_am654: Update OTAPDLY writes

mmc: sdhci_am654: Update OTAPDLY writes

According to the latest AM65x Data Manual[1], a different output tap
delay value is optimum for a given speed mode. Therefore, deprecate the
ti,otap-del-sel binding and introduce a new binding for each of the
possible MMC/SD speed modes. If the legacy mode is not found, fall back
to old binding to maintain dts compatibility.

[1] http://www.ti.com/lit/gpn/am6526

Signed-off-by: Faiz Abbas <faiz_abbas@ti.com>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Link: https://lore.kernel.org/r/20200108150920.14547-3-faiz_abbas@ti.com
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>