aco: Clean up emit_mbcnt.

Make it less error-prone and more consistent with other helpers.
Pass the masks as a single argument rather than two.
In wave64 mode, split the argument into low and high halves in
emit_mbcnt rather than where it is called.

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/6699>
1 file changed