dfrph_c_example: Fixed small copy/paste error

Removed urm37 string.  Re-aligned source.

Signed-off-by: Noel Eck <noel.eck@intel.com>

examples/c/dfrph.c

@@ -50,9 +50,7 @@ int main()
         return(1);
     }
 
-  // Every half a second, sample the URM37 and output the measured
+    // Every half a second, sample the sensor output
-  // distance in cm.
-
     while (shouldRun)
     {
         float volts = 0.0, pH = 0.0;