Ensure php_phongo_bson_visit_int64() has TSRMLS vars if needed

Fixes a 32-bit build error introduced in 22a39d6 for PHPC-313

Author: jmikola

src/bson.c

@@ -530,7 +530,7 @@ bool php_phongo_bson_visit_int64(const bson_iter_t *iter ARG_UNUSED, const char
 #else
 	zval *retval = ((php_phongo_bson_state *)data)->zchild;
 #endif
-
+	TSRMLS_FETCH();
 
 	ADD_ASSOC_INT64(retval, key, v_int64);