drm/tegra: Add call to put_pid()

drm/tegra: Add call to put_pid()

Add a call to put_pid() corresponding to get_task_pid().
host1x_memory_context_alloc() does not take ownership of the PID so we
need to free it here to avoid leaking.

Signed-off-by: Prateek Agarwal <praagarwal@nvidia.com>
Fixes: e09db97889ec ("drm/tegra: Support context isolation")
[mperttunen@nvidia.com: reword commit message]
Signed-off-by: Mikko Perttunen <mperttunen@nvidia.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>
Link: https://patch.msgid.link/20250919-host1x-put-pid-v1-1-19c2163dfa87@nvidia.com