drm/tegra: gem: Add a clarifying comment

Clarify when a fixed IOV address can be used and when a buffer has to
be mapped before the IOVA can be used.

Signed-off-by: Thierry Reding <treding@nvidia.com>
This commit is contained in:
Thierry Reding 2021-03-26 15:51:36 +01:00
commit 476e93205f