drm/amdgpu: Correct the irq types' num of sdma

Fix the issue about TDR-2 will have "fallback timer expired on ring sdma1".
It is because the wrong number of irq types setting.

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