iio: core: Introduce IIO_CHAN_INFO_CALIBWEIGHT

Some devices need the weight of the user to compute other
parameters. One of this devices is Freescale's MMA9553L
(http://www.freescale.com/files/sensors/doc/ref_manual/MMA9553LSWRM.pdf)
that needs the weight of the user to compute the number of calories burnt.

Signed-off-by: Irina Tirdea <irina.tirdea@intel.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
diff --git a/include/linux/iio/iio.h b/include/linux/iio/iio.h
index 5902020..51f1643 100644
--- a/include/linux/iio/iio.h
+++ b/include/linux/iio/iio.h
@@ -40,6 +40,7 @@
 	IIO_CHAN_INFO_INT_TIME,
 	IIO_CHAN_INFO_ENABLE,
 	IIO_CHAN_INFO_CALIBHEIGHT,
+	IIO_CHAN_INFO_CALIBWEIGHT,
 };
 
 enum iio_shared_by {