wincrypt.h: Added MS_ENH_RSA_AES_PROV_XP[_A|_W]. (Thanks to Alon Bar-Lev.)

git-svn-id: svn+ssh://svn.code.sf.net/p/mingw-w64/code/branches/releases/v1.0@4330 4407c894-4637-0410-b4f5-ada5f102cad1