regulator: tps65090: Allow setting the overcurrent wait time

The tps65090 regulator allows you to specify how long you want it to
wait before detecting an overcurrent condition.  Allow specifying that
through the device tree (or through platform data).

Signed-off-by: Doug Anderson <dianders@chromium.org>
Signed-off-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Michael Spang <spang@chromium.org>
Signed-off-by: Sean Paul <seanpaul@chromium.org>
Signed-off-by: Mark Brown <broonie@linaro.org>