staging:iio::hwmon interface client driver.

Direct copy of version proposed for the non staging branch.
Needed here to allow testing of more advanced inkernel
interface code.

Minimal support of simple in, curr and temp attributes
so far.

Signed-off-by: Jonathan Cameron <jic23@kernel.org>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/staging/iio/Makefile b/drivers/staging/iio/Makefile
index ff059d4..5075291 100644
--- a/drivers/staging/iio/Makefile
+++ b/drivers/staging/iio/Makefile
@@ -17,6 +17,8 @@
 
 obj-$(CONFIG_IIO_DUMMY_EVGEN) += iio_dummy_evgen.o
 
+obj-$(CONFIG_IIO_ST_HWMON) += iio_hwmon.o
+
 obj-y += accel/
 obj-y += adc/
 obj-y += addac/