iio: Add tmp006 IR temperature sensor

the TI TMP006 is a non-contact temperature sensor with I2C interface;
it measures the surface temperature of a distance object using a
thermopile to absorb IR energy emitted from the object

the sensor has two channels: IR sensor voltage (16-bit) and reference
temperature of the chip (14-bit); datasheet is here:
http://www.ti.com/lit/ds/symlink/tmp006.pdf

v2 (thanks to Grygorii Strashko, Lars-Peter Clausen, Jonathan Cameron
for review comments):
* power down device on driver remove
* use sign_extend32()
* style cleanup
* add comments what channel raw LSBs mean
* spelling of thermopile

Signed-off-by: Peter Meerwald <pmeerw@pmeerw.net>
Cc: Grygorii Strashko <grygorii.strashko@ti.com>
Cc: Lars-Peter Clausen <lars@metafoo.de>
Cc: Jonathan Cameron <jic23@kernel.org>
Cc: LM Sensors <lm-sensors@lm-sensors.org>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
diff --git a/drivers/iio/temperature/Kconfig b/drivers/iio/temperature/Kconfig
new file mode 100644
index 0000000..372f8fb
--- /dev/null
+++ b/drivers/iio/temperature/Kconfig
@@ -0,0 +1,16 @@
+#
+# Temperature sensor drivers
+#
+menu "Temperature sensors"
+
+config TMP006
+	tristate "TMP006 infrared thermopile sensor"
+	depends on I2C
+	help
+	  If you say yes here you get support for the Texas Instruments
+	  TMP006 infrared thermopile sensor.
+
+	  This driver can also be built as a module. If so, the module will
+	  be called tmp006.
+
+endmenu