drm/radeon: delete radeon_fence_process in is_signaled, no deadlock

In the Linux kernel, the following vulnerability has been resolved:

drm/radeon: delete radeon_fence_process in is_signaled, no deadlock

Delete the attempt to progress the queue when checking if fence is signaled. This avoids deadlock.

dma-fence_ops::signaled can be called with the fence lock in unknown state. For radeon, the fence lock is also the wait queue lock. This can cause a self deadlock when signaled() tries to make forward progress on the wait queue. But advancing the queue is unneeded because incorrectly returning false from signaled() is perfectly acceptable.

(cherry picked from commit 527ba26e50ec2ca2be9c7c82f3ad42998a75d0db)