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 <[e-mail]>
Signed-off-by: Doug Anderson <[e-mail]>
Tested-by: Stephen Warren <[e-mail]>
Signed-off-by: Mark Brown <[e-mail]>

drivers/regulator/tps65090-regulator.c

···
 		ri = &pmic[num];
 		ri->dev = &pdev->dev;
 		ri->desc = &tps65090_regulator_desc[num];
-		ri->overcurrent_wait_valid = tps_pdata->overcurrent_wait_valid;
-		ri->overcurrent_wait = tps_pdata->overcurrent_wait;
+		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.