QXmlStream: fix generating ERROR enum value

It was changed from ERROR to XML_ERROR to disambiguate static variables
in d3f8d7fd4140b269532e2daca8eb5cbfe28ed465. Make the change in
qxmlstream.g, so that generating the C++ code doesn't revert it.

Change-Id: Ie51955a2b013ce8d9580ce64f708598f9a103754
Reviewed-by: Marc Mutz <marc.mutz@qt.io>
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@qt.io>
(cherry picked from commit a982b67538155500269418b9fec81f19ff019510)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>

src/corelib/serialization/qxmlstream.g

@@ -58,7 +58,7 @@
 %token PCDATA "PCDATA"
 
 -- error
-%token ERROR
+%token XML_ERROR
 
 -- entities
 %token PARSE_ENTITY
@@ -251,7 +251,7 @@ bool QXmlStreamReaderPrivate::parse()
             } else switch (token_char) {
             case 0xfffe:
             case 0xffff:
-                token = ERROR;
+                token = XML_ERROR;
                 break;
             case '\r':
                 token = SPACE;

src/corelib/serialization/qxmlstreamgrammar_p.h

@@ -44,7 +44,6 @@ public:
         ENTITY = 32,
         ENTITY_DONE = 45,
         EQ = 14,
-        XML_ERROR = 43,
         FIXED = 39,
         HASH = 6,
         ID = 48,
@@ -81,6 +80,7 @@ public:
         UNRESOLVED_ENTITY = 46,
         VERSION = 55,
         XML = 54,
+        XML_ERROR = 43,
 
         ACCEPT_STATE = 416,
         RULE_COUNT = 270,