drm/amdgpu/userq: unmap is to be called before freeing doorbell/wptr bo

drm/amdgpu/userq: unmap is to be called before freeing doorbell/wptr bo

Unmap the queue after freeing doorbell and wptr memory is completely
wrong. Any operation on the queue needs the doorbell and wptr to be
valid and hence fixing the ordering.

Also since we are using amdgpu_bo_reserve in non interruptrable mode
so there is no need to check for its return values.

Signed-off-by: Sunil Khatri <sunil.khatri@amd.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>