drm/radeon: drop radeon_ring_force_activity

The reason for the false positives was fixed quite some time ago and since
most engines can still execute NOPs while being locked up it leads to false
negatives.

Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
13 files changed