anv/isl: preventive fixup of VK_EXT_sliced_view_of_3d

What does this MR do and why?

We're not following the HW recommendation in the programming of RENDER_SURFACE_STATE::Depth. This value should be the LOD0 depth.

Even if it doesn't appear to break anything atm, I'm concerned this can cause issues with new tilings (Ys/Tile64).

To implement the correct view depth size reporting we can read the RENDER_SURFACE_STATE value from the shader instead.