dispatch: properly handle parameter name mismatches in glapitemp.h.

dispatch: properly handle parameter name mismatches in glapitemp.h.

Previously, when code-generating aliased functions in glapitemp.h, we
weren't consistent about which function alias we used to obtain the
parameter names, with the risk that we would generate incorrect code
like this:

  KEYWORD1 void KEYWORD2 NAME(Foo)(GLint x)
  {
    (void) x;
    DISPATCH(Foo, (x), (F, "glFoo(%d);\n", x));
  }
  KEYWORD1 void KEYWORD2 NAME(FooEXT)(GLint y)
  {
    (void) x;
    DISPATCH(Foo, (x), (F, "glFooEXT(%d);\n", x));
  }

At the moment there are no aliased functions with mismatched parameter
names, so this isn't the problem.  But when we introduce GLES1
functions into the dispatch table, there will be
(MapBufferRange/MapBufferRangeEXT).  This patch paves the way for that
by fixing the code generation script to handle the mismatch correctly.

Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Chad Versace <chad.versace@linux.intel.com>