content: css: dump: Handle CALC unit type

We won't actually reach this, because the type won't be SET if
it's CALC.

content/handlers/css/dump.c

@@ -145,6 +145,9 @@ static void dump_css_unit(FILE *stream, css_fixed val, css_unit unit)
 	case CSS_UNIT_Q:
 		fprintf(stream, "q");
 		break;
+	case CSS_UNIT_CALC:
+		fprintf(stream, "calc()");
+		break;
 	}
 }