freedreno/ir3/sched: avoid getting stuck on addr conflicts

freedreno/ir3/sched: avoid getting stuck on addr conflicts

When we get in a scenario where we cannot schedule any more instructions
due to address register conflict, clone the instruction that writes the
address register, and switch the remaining unscheduled users for the
current address register over to the new clone.

This is simpler and more robust than the previous attempt (which tried
and sometimes failed to ensure all other dependencies of users of the
address register were scheduled first).. hint it would try to schedule
instructions that were not actually needed for any output value.

We probably need to do the same with predicate register, although so far
it isn't so heavily used so we aren't running into problems with it
(yet).

Signed-off-by: Rob Clark <robclark@freedesktop.org>