Add support for float32 in inference_runner

Change-Id: I1c618be058863a3a2457a849e70b22851aa91b3a
diff --git a/driver_library/src/ethosu.cpp b/driver_library/src/ethosu.cpp
index 2c498a8..40fc909 100644
--- a/driver_library/src/ethosu.cpp
+++ b/driver_library/src/ethosu.cpp
@@ -64,6 +64,8 @@
         return 1;
     case tflite::TensorType::TensorType_INT16:
         return 2;
+    case tflite::TensorType::TensorType_FLOAT32:
+        return 4;
     default:
         throw EthosU::Exception("Unsupported tensor type");
     }