linux-phytec-fsl

drm/nouveau/ltc: add hooks for invalidate and flush

These are useful for systems without a coherent CPU/GPU bus. For such
systems we may need to maintain the L2 ourselves.

Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>