The SPIR-V backend will emit a default control point phase. Inserting
inputs into the IR allows handling of declarations via the usual path
instead of an ad hoc implementation which may not match later changes
to input handling.
In SPIR-V the address must include the invocation id, but in TPF it
is implicit. Move the register index up one slot and insert an
OUTPOINTID relative address.
Normalise the incoming vkd3d_shader_instruction IR to the shader model 6
pattern. This allows generation of a single patch constant function in
SPIR-V.
