drm/i915: Sanitize DMC/CSR ucode cleanup code

commit ebae38d0
Author: Animesh Manna <animesh.manna@intel.com>
Date:   Wed Oct 28 23:58:55 2015 +0200

    drm/i915/gen9: csr_init after runtime pm enable

moved the DMC/CSR initialization later during driver loading, but didn't
move the cleanup earlier correspondingly during unloading. Fix this up.

Signed-off-by: Imre Deak <imre.deak@intel.com>
Reviewed-by: David Weinehall <david.weinehall@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1453209992-25995-2-git-send-email-imre.deak@intel.com