drm/amdgpu: Fix documentaion for dm_dmub_outbox1_low_irq

Fix make htmldocs complaint:
./drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c:628: warning: Excess function parameter 'interrupt_params' description in 'DMUB_TRACE_MAX_READ'

v2:
Moved DMUB_TRACE_MAX_READ macro above function documentation

Signed-off-by: Anson Jacob <Anson.Jacob@amd.com>
CC: Harry Wentland <harry.wentland@amd.com>
Acked-by: Alex Deucher <alexander.deucher@amd.com>
Reviewed-by: Harry Wentland <harry.wentland@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>