spirv: Add a dst/src type to image deref loads/stores coming from OpAtomic{Load,Store}

spirv: Add a dst/src type to image deref loads/stores coming from OpAtomic{Load,Store}

nir_to_dxil() uses those types to pick the right operation overload,
and atomic loads/stores are no different from their non-atomic
counterpart apart from the atomicity property, so it makes sense to
pass a type to the deref_{load,store} intrinsic in that case too.

Suggested-by: Jesse Natalie <jenatali@microsoft.com>
Reviewed-by: Jesse Natalie <jenatali@microsoft.com>
Reviewed-by: Jason Ekstrand <jason.ekstrand@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/16926>