iio: frequency: admv1014: return -EINVAL directly

Remove extra step where the error code is assigned to the `ret`
variable.

Return instead error code directly.

Signed-off-by: Antoniu Miclaus <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Jonathan Cameron <[e-mail]>

drivers/iio/frequency/admv1014.c

···
 	chip_id = FIELD_GET(ADMV1014_CHIP_ID_MSK, chip_id);
 	if (chip_id != ADMV1014_CHIP_ID) {
 		dev_err(&spi->dev, "Invalid Chip ID.\n");
-		ret = -EINVAL;
-		return ret;
+		return -EINVAL;
 	}
 
 	ret = __admv1014_spi_update_bits(st, ADMV1014_REG_QUAD,