nir: Make the nir_builder *_imm helpers consistently handle bit size.

We always want to demote the y to the bit size of the ssa def, but also
want to sanity check that our input and our masking is big enough.

Reviewed-by: Kristian H. Kristensen <hoegsberg@google.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/6378>
1 file changed