regulator: axp20x: add support for set_ramp_delay for AXP209

Hello Olliver Schinagl,

This is a semi-automatic email about new static checker warnings.

The patch d29f54df8b16: "regulator: axp20x: add support for set_ramp_delay for AXP209" from Dec 11, 2018, leads to the following Smatch complaint:

drivers/regulator/axp20x-regulator.c:375 axp20x_set_ramp_delay()
warn: variable dereferenced before check 'rdev' (see line 369)

drivers/regulator/axp20x-regulator.c
368 {

   369		struct axp20x_dev *axp20x = rdev_get_drvdata(rdev);
                                                             ^^^^
   370		const struct regulator_desc *desc = rdev->desc;
                                                    ^^^^^^^^^^

Dereferences

371 u8 reg, mask, enable, cfg = 0xff;
372 const int *slew_rates;
373 int rate_count = 0;
374
375 if (!rdev)

                    ^^^^^

Check too late.

376 return -EINVAL;
377

regards,
dan carpenter