drm/amdgpu: change trace event parameter name from 'direct' to 'immediate'

s/direct/immediate/g

amdgpu vm has renamed parameter name from 'direct' to 'immedate'.
however, the trace event is not updated yet.

Signed-off-by: Kevin Wang <kevin1.wang@amd.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>