drm/amdgpu/pm: Drop redundant setting code for pcie lanes

Drop redundant setting code for pcie.lanes. It overwrites
the value get from pptable

Signed-off-by: Ma Jun <Jun.Ma2@amd.com>
Acked-by: Yang <Wang&lt;kevinyang.wang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>