dx9 erroroneously reports no power of 2 texture support

[zhao]

dxGraphicStateGuardian9.cxx never checks whether or not power of 2 texture support is supported by the graphics card
and causes the GSG to throw an erroraneous error message when making buffers. (Loading normal textures appears to have a hack in dxTextureContext to check for this functionality.)

This fix, Line 2581 dxGraphicStateGuardian9.cxx (add anywhere in DXGraphicsStateGuardian9::reset near the end of the function), will correct the check.l

  //zhao 5_18
  _supports_tex_non_pow2 = !(d3d_caps.TextureCaps & D3DPTEXTURECAPS_POW2);