radeonsi: pass -O halt_waves to umr for hang debugging

radeonsi: pass -O halt_waves to umr for hang debugging

This will give us meaningful wave information in the case of a hang where
shaders are still running in an infinite loop.

Note that we call umr multiple times for different sections of the ddebug
hang dump, and so the wave information will not necessarily match up
between sections.

Reviewed-by: Marek Olšák <marek.olsak@amd.com>