drm/amdgpu: drop the incorrect soft_reset for SRIOV

It's incorrect to do soft reset for SRIOV, when GFX
hang the WREG would stuck there becuase it goes KIQ way.

the GPU reset counter is incorrect: always increase twice
for each timedout

Signed-off-by: Monk Liu <Monk.Liu@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>