JSON: Correcting bad sensor names

Signed-off-by: malikabh <abhishek.malik@intel.com>

src/dfrec/dfrec.json

@@ -3,7 +3,7 @@
     "Description": "DFRobot EC Meter Library",
     "Sensor Class":
     {
-        "dfrec":
+        "DFREC":
         {
             "Name": "Analog Electrical Conductivity (EC) Sensor",
             "Description": "The driver was tested with the DFRobot EC Analog Sensor. This device measure the electrical conductivity of an aqueous solution.  The included probe is a K=1 model. Calibration is somewhat complicated - see the DFRobot wiki for instructions on calibration.  Functions are provided to supply the appropriate values.  By default, the values used in the DFRobot arduino example are used.",
@@ -36,4 +36,4 @@
             }
         }
     }
-}
+}