drm/amdgpu: extended waiting SRIOV VF reset completion timeout to 10s

For the ASIC has big FB, it need more time to clear FB during reset.
This change extended SRIOV VF waiting reset completion timeout from 5s
to 10s.

Signed-off-by: Zhigang Luo <zhigang.luo@amd.com>
Acked-by: Shaoyun Liu <shaoyun.liu@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>