drm/amdgpu:bypass avfs event manager for sriov

This patch is used for virtualization support. In virtualization case,
the initialization sequences are not totally the same as
non-Virtualization's. The avfs event manager should be bypassed if in
SRIOV virtualization case. At the same, this patch will also bypass
starting SMC within SRIOV in FIJI, so the SMU firmware loading will be
avoid, which is required in SRIOV.

Signed-off-by: Frank Min <Frank.Min@amd.com>
Signed-off-by: Xiangliang Yu <Xiangliang.Yu@amd.com>
Signed-off-by: Trigger Huang <trigger.huang@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>