Having registered debugfs files globally causes
the files to not show up on the second, third
etc.. card in the system.

v2: fix crash on module unloading
v3: fix space indentation
Signed-off-by: NChristian König <deathsimple@vodafone.de>
Reviewed-by: NAlex Deucher <alexander.deucher@amd.com>
Reviewed-by: NJerome Glisse <jglisse@redhat.com>
Signed-off-by: NDave Airlie <airlied@redhat.com>