drm/amdgpu: Change nbio v7.9 xcp status definition

PARTITION_MODE field in PARTITION_COMPUTE_STATUS register is defined as
below by firmware.

	SPX = 0, DPX = 1, TPX = 2, QPX = 3, CPX = 4

Change driver definition accordingly.

Signed-off-by: Lijo Lazar <lijo.lazar@amd.com>
Reviewed-by: Hawking Zhang <Hawking.Zhang@amd.com>
Reviewed-by: Le Ma <le.ma@amd.com>
Acked-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>