drm/amdgpu: use different irq ring ID for Vega20 page queues

Vega20 uses ring id 1 for page queues EOP irq while previous
ASICs take ring id 3.

Signed-off-by: Evan Quan <evan.quan@amd.com>
Acked-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>