iio: magn: bmc150: Use vsprintf extension %pe for symbolic error name

Utilize %pe format specifier from vsprintf while printing error logs
with dev_err(). Discards the use of unnecessary explicit casting and
prints symbolic error name which might prove to be convenient during
debugging.
Signed-off-by: Nishant Malpani <nish.malpani25@gmail.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/iio/magnetometer/bmc150_magn_spi.c

@@ -22,8 +22,8 @@ static int bmc150_magn_spi_probe(struct spi_device *spi)
 
 	regmap = devm_regmap_init_spi(spi, &bmc150_magn_regmap_config);
 	if (IS_ERR(regmap)) {
-		dev_err(&spi->dev, "Failed to register spi regmap %d\n",
-			(int)PTR_ERR(regmap));
+		dev_err(&spi->dev, "Failed to register spi regmap: %pe\n",
+			regmap);
 		return PTR_ERR(regmap);
 	}
 	return bmc150_magn_probe(&spi->dev, regmap, spi->irq, id->name);