amd/amdgpu/sriov swSMU disable for sriov

For boards greater than ARCTURUS, and under sriov platform,
swSMU is not supported because smu ip block is commented at
guest driver.

Generally for sriov, initialization of smu is moved to host driver.
Thus, smu sw_init and hw_init will not be executed at guest driver.

Without sw structure being initialized in guest driver, swSMU cannot
declare to be supported.

Signed-off-by: Jack Zhang <Jack.Zhang1@amd.com>
Reviewed-by: Kevin Wang <kevin1.wang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>