drm/amdgpu: Add sysfs nodes to get xcp details

Add partition config nodes in sysfs to get resource instance details for
a particular partition mode. A resource could be anything like an xcc,
vcn decoder, system dma units etc.

Details of various resource instances are available under
/sys/bus/pci/devices/.../compute_partition_config/

Select a partition configuration:
/sys/bus/pci/devices/.../compute_partition_config/xcp_config

Number of instances of a resource:
/sys/bus/pci/devices/.../compute_partition_config/<rsrc_name>/num_inst

Total partitions sharing the resource:
/sys/bus/pci/devices/.../compute_partition_config/<rsrc_name>/num_shared

v2: Update node name as per spec

Signed-off-by: Lijo Lazar <lijo.lazar@amd.com>
Signed-off-by: Asad Kamal <asad.kamal@amd.com>
Reviewed-by: Hawking Zhang <Hawking.Zhang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>