amdgpu: Add deadlock detection test suit.

amdgpu: Add deadlock detection test suit.

Adding initial tests for locks detection when SW
scheduler FIFO is full.

The test works by submitting a batch of identical commands which make the CP
stall waiting for condition to become true. The condition is later satisfied
form a helper thread. Other events that happen during this time
might create deadlock situations. One such example is GPU reset
triggered by this stall when  amdgpu_lockup_timeout != 0.

v2:
Increase the delay from 2 to 100 ms.
Comment out the compute test until it's working.
Typos fix.

Signed-off-by: Andrey Grodzovsky <andrey.grodzovsky@amd.com>
Reviewed-by: Christian König <christian.koenig@amd.com>