pan/bi: Extend the bi_builder to support type variants correctly

pan/bi: Extend the bi_builder to support type variants correctly

Some opcodes come with both type and size variants. Right now, only the
size is taken into account. Extend the builder to provide wrappers that
take a nir_type in addition to the bitsize.

While at it, fix wrappers taking a compare operator to use the proper
.{i,s,u} variant based on the comparison (equal and non-equal should
use .i, other comparisons should use .{u,s}).

Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
Reviewed-by: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/9520>