drm/amd/amdgpu: Convert ring debugfs entries to binary

They now emit ring data in binary which will be read/written by
the userspace tool umr shortly.

Signed-off-by: Tom St Denis <tom.stdenis@amd.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>