Add support for uint16_t to RESCALE

Update ref-model RESCALE op to support UINT16 conversions
Add testing for RESCALE UINT16 and ERROR_IFs

Signed-off-by: Jeremy Johnson <jeremy.johnson@arm.com>
Change-Id: Ic6e6e53de1f0b054bedb9e6ba3856e7475498aba
diff --git a/reference_model/src/quant_util.h b/reference_model/src/quant_util.h
index 8c1b391..3b7674d 100644
--- a/reference_model/src/quant_util.h
+++ b/reference_model/src/quant_util.h
@@ -114,7 +114,7 @@
     static bool is_integer(DType dtype)
     {
         if (dtype == DType_INT4 || dtype == DType_INT8 || dtype == DType_UINT8 || dtype == DType_INT16 ||
-            dtype == DType_INT32 || dtype == DType_INT48)
+            dtype == DType_UINT16 || dtype == DType_INT32 || dtype == DType_INT48)
         {
             return true;
         }