If we don't reset ctx.vm_cnt/gpr_map/etc, this will spam a lot of
s_waitcnt instructions.
Signed-off-by: Rhys Perry <pendingchaos02@gmail.com>
Reviewed-by: Timur Kristóf <timur.kristof@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/17207>