iommu/tegra: gart: Remove pr_fmt and clean up includes

Remove unneeded headers inclusion and sort the headers in alphabet order.
Remove pr_fmt macro since there is no pr_*() in the code and it doesn't
affect dev_*() functions.

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
Acked-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>