wined3d: Set D3DPTEXTURECAPS_TRANSPARENCY.

It indicates support of colorkey transparency on textures, so set it because 
wined3d supports it. Fixes transparency problems in Forsaken.
diff --git a/dlls/wined3d/directx.c b/dlls/wined3d/directx.c
index bd7f68b..c55d66c 100644
--- a/dlls/wined3d/directx.c
+++ b/dlls/wined3d/directx.c
@@ -3135,6 +3135,7 @@
 
     pCaps->TextureCaps =  WINED3DPTEXTURECAPS_ALPHA              |
                           WINED3DPTEXTURECAPS_ALPHAPALETTE       |
+                          WINED3DPTEXTURECAPS_TRANSPARENCY       |
                           WINED3DPTEXTURECAPS_BORDER             |
                           WINED3DPTEXTURECAPS_MIPMAP             |
                           WINED3DPTEXTURECAPS_PROJECTED          |