drm/nouveau: sgdma: add comment around suspiscious error handler
drm/nouveau: sgdma: add comment around suspiscious error handler

Common programming sense dictates that resources allocated by a function
are freed by this function should it fails, but this is not the case for
the allocated structure of nouveau_sgdma_create_ttm(). It seems that
n00b contributors attempt to fix this one like bugs flying towards a bug
zapper, so add a comment to hopefully prevent this from happening
anymore.

Signed-off-by: Alexandre Courbot <301cd6a3ea50a894b4b51e385c5eb12b9a4ffc0c@nvidia.com>
Signed-off-by: Ben Skeggs <d9f27fb07c1e9f131223ad827fa5179f3846c30b@redhat.com>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs