regulator: lp87565: Simplify lp87565_buck_set_ramp_delay

Use rdev->regmap/&rdev->dev instead of lp87565->regmap/lp87565->dev.
In additional, the lp87565->dev actually is the parent mfd device,
so the dev_err message is misleading here with lp87565->dev.

Signed-off-by: Axel Lin <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Mark Brown <[e-mail]>

drivers/regulator/lp87565-regulator.c

···
 				       int ramp_delay)
 {
 	int id = rdev_get_id(rdev);
-	struct lp87565 *lp87565 = rdev_get_drvdata(rdev);
 	unsigned int reg;
 	int ret;
 
···
 	else
 		reg = 0;
 
-	ret = regmap_update_bits(lp87565->regmap, regulators[id].ctrl2_reg,
+	ret = regmap_update_bits(rdev->regmap, regulators[id].ctrl2_reg,
 				 LP87565_BUCK_CTRL_2_SLEW_RATE,
 				 reg << __ffs(LP87565_BUCK_CTRL_2_SLEW_RATE));
 	if (ret) {
-		dev_err(lp87565->dev, "SLEW RATE write failed: %d\n", ret);
+		dev_err(&rdev->dev, "SLEW RATE write failed: %d\n", ret);
 		return ret;
 	}