When modifying panfrost_devfreq_target() to support a device without a
regulator defined I missed the check on the error path. Let's add it.
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Fixes: e21dd290881b ("drm/panfrost: Enable devfreq to work without regulator")
Signed-off-by: Steven Price <steven.price@arm.com>
Signed-off-by: Rob Herring <robh@kernel.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20190822093218.26014-1-steven.price@arm.com
        if (err) {
                dev_err(dev, "Cannot set frequency %lu (%d)\n", target_rate,
                        err);
-               regulator_set_voltage(pfdev->regulator, pfdev->devfreq.cur_volt,
-                                     pfdev->devfreq.cur_volt);
+               if (pfdev->regulator)
+                       regulator_set_voltage(pfdev->regulator,
+                                             pfdev->devfreq.cur_volt,
+                                             pfdev->devfreq.cur_volt);
                return err;
        }