Fix for missing airflow in interface description

Added airflow in top-level interface description.

Tested:
   verified using YAML editor, Compiles correctly

Signed-off-by: Basheer Ahmed Muddebihal <basheerx.muddebihal@intel.com>
Change-Id: Idc546ba27049f244a07d0e443bc57b1f8e335ad3
diff --git a/yaml/xyz/openbmc_project/Sensor/Value.interface.yaml b/yaml/xyz/openbmc_project/Sensor/Value.interface.yaml
index e825c9a..3c55da7 100644
--- a/yaml/xyz/openbmc_project/Sensor/Value.interface.yaml
+++ b/yaml/xyz/openbmc_project/Sensor/Value.interface.yaml
@@ -11,6 +11,7 @@
       power
       energy
       utilization
+      airflow
       pressure
 
     Any service implementing Sensor.Value on one or more objects must