aco/util: override default assignment operator for bitfield helpers

Otherwise, the default assignment operator copies the whole uint,
not just few bits we are interested in.

Reviewed-by: Rhys Perry <pendingchaos02@gmail.com>
Fixes: e7559da7570 ("aco: add bitfield array helper classes")
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/22154>
1 file changed