Add HidD_GetProductString, HidD_SetNumInputBuffers, and HidD_GetNumInputBuffers
function prototypes to hidsid.h header.


git-svn-id: https://mingw-w64.svn.sourceforge.net/svnroot/mingw-w64@5868 4407c894-4637-0410-b4f5-ada5f102cad1