drm/amdgpu/swSMU: use the smu11 power source helper for navi1x

The smu_v11_0 version works for navi1x.

Bug: https://gitlab.freedesktop.org/drm/amd/issues/1043


Reviewed-by: Evan Quan <evan.quan@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>