Remove the type field from the sensor value structure. All values will
have the type previously defined by SENSOR_VALUE_TYPE_INT_PLUS_MICRO.
This simplifies the interface, as apps will know what value type to
expect. Apps that prefer to use double values can optain them using the
sensor_value_to_double function.
Change-Id: I3588d74258030eb16c3f89d8eead13cca4606b18
Signed-off-by: Bogdan Davidoaia <bogdan.davidoaia@linaro.org>