Description: drm/ttm/nouveau: don't call tt destroy callback on alloc failure.
References:
 https://bugzilla.redhat.com/show_bug.cgi?id=1939686
Notes:
 bwh> From my reading of the fix, the bug did not affect nouveau but
 bwh> all the other ttm-based drivers (amdgpu, qxl, radeon, virtgpu,
 bwh> and vmwgfx).  The fix is to make the API behave the way the
 bwh> other drivers expected it to, and change nouveau accordingly.
 bwh> This will create a potential memory leak in any OOT drivers
 bwh> that were using the API correctly.
Bugs:
upstream: released (5.9-rc1) [5de5b6ecf97a021f29403aa272cb4e03318ef586]
5.10-upstream-stable: N/A "Fixed before branching point"
4.19-upstream-stable: released (4.19.140) [10c8a526b2db1fcdf9e2d59d4885377b91939c55]
4.9-upstream-stable: released (4.9.298) [70f44dfbde027f444412cfb4ea9b485a4c1dec0e]
sid: released (5.7.17-1)
5.10-bullseye-security: N/A "Fixed before branching point"
4.19-buster-security: released (4.19.146-1)
4.9-stretch-security: released (4.9.272-1) [bugfix/all/drm-ttm-nouveau-don-t-call-tt-destroy-callback-on-al.patch]