drm/amdkfd: Improve HWS hang detection and handling

Move HWS hang detection into unmap_queues_cpsch to catch hangs in all
cases. If this happens during a reset, don't schedule another reset
because the reset already in progress is expected to take care of it.

Signed-off-by: Felix Kuehling <Felix.Kuehling@amd.com>
Tested-by: Emily Deng <Emily.Deng@amd.com>
Reviewed-by: shaoyunl <shaoyun.liu@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>