Fix for Mantis #24953.

pgenutil.pas, parse_generic_parameters:
  * set the typesym of the newly created def so that inline specializations in pexpr.pas, sub_expr can check it correctly

git-svn-id: http://svn.freepascal.org/svn/fpc/trunk@25410 3ad0048d-3df7-0310-abae-a5850022a9f2