drm/amdgpu: refine query function of mmhub EDC counter in vg20

Add codes to print the detail EDC info for the subblock of mmhub

v2: Move the EDC_CNT registers' defintion from mmhub_9_4 header
files to mmhub_1_0 ones. Add mmhub_v1_0_ prefix for the local
static variable and function.

v3: squash in DC fix

Signed-off-by: Dennis Li <dennis.li@amd.com>
Reviewed-by: Hawking Zhang <Hawking.Zhang@amd.com>
Reviewed-by: Tao Zhou <tao.zhou1@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>