iio: gyro: bmg160_spi: 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/gyro/bmg160_spi.c

@@ -19,8 +19,8 @@ static int bmg160_spi_probe(struct spi_device *spi)
 
 	regmap = devm_regmap_init_spi(spi, &bmg160_regmap_spi_conf);
 	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);
 	}