drm/amdgpu/gfx10: fix CSIB handling

[ Upstream commit 683308af030cd9b8d3f1de5cbc1ee51788878feb ]

We shouldn't return after the last section.
We need to update the rest of the CSIB.

Reviewed-by: Rodrigo Siqueira <siqueira@igalia.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>