aco: Extract uniform if handling to separate functions.

Currently we only use this for uniform ifs that come from NIR,
but we are going to need to use it with some NGG parts as well.

Signed-off-by: Timur Kristóf <timur.kristof@gmail.com>
Reviewed-by: Daniel Schürmann <daniel@schuermann.dev>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/3576>
1 file changed