Return D3D_OK for Set/GetRenderState calls with D3DRS_ZVISIBLE

[WinterSnowfall]

Tests on Windows XP have shown that these particular calls don't actually error out for D3DRS_ZVISIBLE, but simply return D3D_OK. Also, the default value of D3DRS_ZVISIBLE is 0.

[elishacloud]

I believe this is a good change.

I just tested and it seems like SetRenderState() and GetRenderState() should always return DD_OK as long as the State is less than or equal to 255, even if unsupported States are specified. In fact, it might even return DD_OK if the state is greater than 255. I don't see anything in the documentation about it returning anything bu DD_OK.