regulator: tps65090: Fix tps65090 crash on Tegra Dalmore

The patch (60e91b5 regulator: tps65090: Allow setting the overcurrent
wait time) introduced a crash on Tegra Dalmore.  On Dalmore the device
tree doesn't have an entry for all of the FETs so it leaves tps_pdata
NULL in some cases.  Add a check for NULL like the rest of the code
does.
Reported-by: Olof Johansson <olof@lixom.net>
Signed-off-by: Doug Anderson <dianders@chromium.org>
Tested-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Mark Brown <broonie@linaro.org>

drivers/regulator/tps65090-regulator.c

@@ -431,8 +431,11 @@ static int tps65090_regulator_probe(struct platform_device *pdev)
 		ri = &pmic[num];
 		ri->dev = &pdev->dev;
 		ri->desc = &tps65090_regulator_desc[num];
-		ri->overcurrent_wait_valid = tps_pdata->overcurrent_wait_valid;
+		if (tps_pdata) {
+			ri->overcurrent_wait_valid =
+				tps_pdata->overcurrent_wait_valid;
 			ri->overcurrent_wait = tps_pdata->overcurrent_wait;
+		}
 
 		/*
 		 * TPS5090 DCDC support the control from external digital input.