drm/amdgpu/pm: enable vcn busy sysfs for GC 9.3.0

Make it visible for the all GC 9.3.0 chips that support it.

Reviewed-by: Lijo Lazar <lijo.lazar@amd.com>
Reviewed-by: Kenneth Feng <kenneth.feng@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>