iio:chemical:sps30: Convert sysfs sprintf/snprintf family to sysfs_emit

Fix the following coccicheck warning:
./drivers/iio/chemical/sps30.c:414:8-16: WARNING:
use scnprintf or sprintf
Signed-off-by: Tian Tao <tiantao6@hisilicon.com>
Link: https://lore.kernel.org/r/1618216751-1678-2-git-send-email-tiantao6@hisilicon.comSigned-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/iio/chemical/sps30.c

@@ -411,7 +411,7 @@ static ssize_t cleaning_period_available_show(struct device *dev,
 					      struct device_attribute *attr,
 					      char *buf)
 {
-	return snprintf(buf, PAGE_SIZE, "[%d %d %d]\n",
+	return sysfs_emit(buf, "[%d %d %d]\n",
 			  SPS30_AUTO_CLEANING_PERIOD_MIN, 1,
 			  SPS30_AUTO_CLEANING_PERIOD_MAX);
 }