drm/amdgpu/gfx_v8_0: Reorder the gfx, kiq and kcq rings test sequence

The kiq ring and the very first compute ring may fail occasionally
if they are tested directly following kiq_kcq_enable.

Insert the gfx ring test before kiq ring test to delay the kiq and kcq
ring tests will fix the issue.

Acked-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Tiecheng Zhou <Tiecheng.Zhou@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>