drm/amdgpu: adjust timeout for ib_ring_tests(v2)

issue:
sometime GFX/MM ib test hit timeout under SRIOV env, root cause
is that engine doesn't come back soon enough so the current
IB test considered as timed out.

fix:
for SRIOV GFX IB test wait time need to be expanded a lot during
SRIOV runtimei mode since it couldn't really begin before GFX engine
come back.

for SRIOV MM IB test it always need more time since MM scheduling
is not go together with GFX engine, it is controled by h/w MM
scheduler so no matter runtime or exclusive mode MM IB test
always need more time.

v2:
use ring type instead of idx to judge

Signed-off-by: Monk Liu <Monk.Liu@amd.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>