accel/ivpu: Update debugfs to latest changes in DRM

Use new drm debugfs helpers. This is needed after changes from
commit 78346ebf9f94 ("drm/debugfs: drop debugfs_init() for the render
and accel node v2").

Reviewed-by: Jeffrey Hugo <quic_jhugo@quicinc.com>
Signed-off-by: Stanislaw Gruszka <stanislaw.gruszka@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230907072610.433497-1-stanislaw.gruszka@linux.intel.com