aco: restrict scheduling depending on max_waves

aco: restrict scheduling depending on max_waves

Previously, we allowed all shaders to reduce the number of max_waves to as low as 5.
Restricting this on shaders with low register demand, increases the total number of waves
while the VMEM def-use distances hardly change.
This patch also changes the max number of move operations per MEM instruction.

Reviewed-by: Rhys Perry <pendingchaos02@gmail.com>