drm/amdgpu: Use PSP to program IH_RB_CNTL_RING1/2 on SRIOV

This is similar to IH_RB_CNTL programming in
navi10_ih_toggle_ring_interrupts

Signed-off-by: Rohit Khaire <rohit.khaire@amd.com>
Acked-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Horace Chen <horace.chen@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>