drm/amdgpu: cleanup context structure v2

The comment is misleading and incorrect, remove it.

Printing the id is completely meaningless and this practice
can cause a race conditions on command submission.

The flags and hangs fields are completely unused.

Give all fields a common indentation.

v2: remove fpriv reference and unused flags as well, fix debug message.

Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Jammy Zhou <Jammy.Zhou@amd.com>
Reviewed-by: Chunming Zhou <david1.zhou@amd.com>