vkd3d-shader/tpf: Replace sm4 register structs with vkd3d-shader register structs, part 2.
Now that !319 (merged) is merged, we can continue replacing the sm4 register structs with vsir register structs.
This second part takes care of replacing sm4_register with vkd3d_shader_register.
Following patches in my use_vkd3d_reg_5 branch.