drm/amdgpu: Clean up errors in amdgpu_trace.h

Fix the following errors reported by checkpatch:

ERROR: space required after that ',' (ctx:VxV)
ERROR: "foo* bar" should be "foo *bar"

Signed-off-by: Ran Sun <sunran001@208suo.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>