[PATCH] windowscodecs: Fix an MSVC warning about pNumericRepresentation.

[Vincent Povirk]

If the enum is for some reason not DWORD-sized, an intermediate
variable would get us the wrong behavior for binary compatibility.
We'd be assigning a different sized value to the caller's DWORD-sized
variable. Of course, casting would break if Wine or winelib calls the
function internally.

It seems to me that neither approach is really safer, but casting
allows for better code sharing.