habanalabs: Call put_pid() when releasing control device

The refcount of the "hl_fpriv" structure is not used for the control
device, and thus hl_hpriv_put() is not called when releasing this
device.
This results with no call to put_pid(), so add it explicitly in
hl_device_release_ctrl().
Signed-off-by: Tomer Tayar <ttayar@habana.ai>
Reviewed-by: Oded Gabbay <ogabbay@kernel.org>
Signed-off-by: Oded Gabbay <ogabbay@kernel.org>

drivers/misc/habanalabs/common/device.c

@@ -117,6 +117,8 @@ static int hl_device_release_ctrl(struct inode *inode, struct file *filp)
 	list_del(&hpriv->dev_node);
 	mutex_unlock(&hdev->fpriv_list_lock);
 
+	put_pid(hpriv->taskpid);
+
 	kfree(hpriv);
 
 	return 0;