drm/amdgpu: init SDMA v6 microcode with PSP load type

Update to use new SDMA UCODE ID when init sdma microcode for sdma6
with psp front door load type.

Signed-off-by: Likun Gao <Likun.Gao@amd.com>
Reviewed-by: Hawking Zhang <Hawking.Zhang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>