F32->F16 Convert operator

PiperOrigin-RevId: 409036598
diff --git a/src/operator-strings.c b/src/operator-strings.c
index d4d6266..3db439f 100644
--- a/src/operator-strings.c
+++ b/src/operator-strings.c
@@ -54,6 +54,8 @@
       return "Constant Pad (ND, X32)";
     case xnn_operator_type_convert_nc_f16_f32:
       return "Convert (NC, F16, F32)";
+    case xnn_operator_type_convert_nc_f32_f16:
+      return "Convert (NC, F32, F16)";
     case xnn_operator_type_convolution_nhwc_f16:
       return "Convolution (NHWC, F16)";
     case xnn_operator_type_convolution_nhwc_f32: