aco: don't store byte-aligned short stores

The ISA docs don't seem to say if this is allowed, so just assume short
stores require short alignment.

Signed-off-by: Rhys Perry <pendingchaos02@gmail.com>
Reviewed-by: Daniel Schürmann <daniel@schuermann.dev>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/5207>
1 file changed