iio: adis162xx: fix low-power docs & reports

All current ADIS162XX drivers have incorrect values defined via comments.
Also, when an error is reported the printed value is incorrect.

The functionality itself isn't affected, so it's not a critical issue.

And since the change is trivial, it was included in a single patch that
fixes these in one go. All values were correlated with the ones specified
in the data-sheets.

Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
diff --git a/drivers/iio/accel/adis16209.c b/drivers/iio/accel/adis16209.c
index f2dc3a5..01dd02f 100644
--- a/drivers/iio/accel/adis16209.c
+++ b/drivers/iio/accel/adis16209.c
@@ -73,7 +73,7 @@
 #define  ADIS16209_STAT_FLASH_UPT_FAIL_BIT	2
 /* Power supply above 3.625 V */
 #define  ADIS16209_STAT_POWER_HIGH_BIT		1
-/* Power supply below 3.15 V */
+/* Power supply below 2.975 V */
 #define  ADIS16209_STAT_POWER_LOW_BIT		0
 
 #define ADIS16209_CMD_REG			0x3E
@@ -241,7 +241,7 @@ static const char * const adis16209_status_error_msgs[] = {
 	[ADIS16209_STAT_SPI_FAIL_BIT] = "SPI failure",
 	[ADIS16209_STAT_FLASH_UPT_FAIL_BIT] = "Flash update failed",
 	[ADIS16209_STAT_POWER_HIGH_BIT] = "Power supply above 3.625V",
-	[ADIS16209_STAT_POWER_LOW_BIT] = "Power supply below 3.15V",
+	[ADIS16209_STAT_POWER_LOW_BIT] = "Power supply below 2.975V",
 };
 
 static const struct adis_data adis16209_data = {