upm-c: added doxygen tags to generate documentation for C APIs

Signed-off-by: Mihai Tudor Panu <mihai.tudor.panu@intel.com>

src/gp2y0a/gp2y0a.h

@@ -34,6 +34,14 @@
 #include "upm.h"
 #include "mraa/aio.h"
 
+/**
+ * @file gp2y0a.h
+ * @library gp2y0a
+ * @brief C API for GP2Y0A IR Proximity Sensors
+ *
+ * @include gp2y0a.c
+ */
+
 /**
  * device context
  */
@@ -43,32 +51,6 @@ typedef struct _gp2y0a_context {
     int                         a_res;
 } *gp2y0a_context;
 
-/**
- * @brief GP2Y0A-based IR Proximity Sensor library
- * @defgroup gp2y0a libupm-gp2y0a
- * @ingroup seeed analog light
- */
-
-/**
- * @library gp2y0a
- * @sensor gp2y0a
- * @comname GP2Y0A IR Proximity Sensor
- * @altname Grove 80cm IR Proximity Sensor
- * @type light
- * @man seeed
- * @con analog
- *
- * @brief API for the GP2Y0A family of IR Proximity Sensors
- *
- * Sensors of this family return an analog voltage corresponding to
- * the distance of an object from the sensor. The voltage is lower
- * when objects are far away; the voltage increases as objects get
- * closer to the sensor.
- *
- * @image html gp2y0a.jpg
- * @snippet gp2y0a.cxx Interesting
- */
-
 /**
  * GP2Y0A sensor init function
  *