headers/pdhmsg: Define `PDH_*` constants with `__MSABI_LONG`

This tries to match how they are defined in the Microsoft header. Despite the
`L` suffix, most of these constants are of type `unsigned long`.

This closes https://github.com/mingw-w64/mingw-w64/pull/151 and
https://github.com/mingw-w64/mingw-w64/pull/152.

Signed-off-by: LIU Hao <lh_mouse@126.com>