iio: magnetometer: ak8974: Simplify with dev_err_probe()

Common pattern of handling deferred probe can be simplified with
dev_err_probe().  Less code and also it prints the error value.
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20200829064726.26268-16-krzk@kernel.orgSigned-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/iio/magnetometer/ak8974.c

@@ -843,15 +843,8 @@ static int ak8974_probe(struct i2c_client *i2c,
 	ret = devm_regulator_bulk_get(&i2c->dev,
 				      ARRAY_SIZE(ak8974->regs),
 				      ak8974->regs);
-	if (ret < 0) {
-		if (ret != -EPROBE_DEFER)
-			dev_err(&i2c->dev, "cannot get regulators: %d\n", ret);
-		else
-			dev_dbg(&i2c->dev,
-				"regulators unavailable, deferring probe\n");
-
-		return ret;
-	}
+	if (ret < 0)
+		return dev_err_probe(&i2c->dev, ret, "cannot get regulators\n");
 
 	ret = regulator_bulk_enable(ARRAY_SIZE(ak8974->regs), ak8974->regs);
 	if (ret < 0) {