drm: amdgpu: Allow NULL pointers at amdgpu_vm_put_task_info()

Allow NULL pointers at amdgpu_vm_put_task_info() as it common practice
for "put" or "free" functions. This avoid an extra check for NULL for
callers.

Reviewed-by: Christian König <christian.koenig@amd.com>
Link: https://lore.kernel.org/r/20250617124949.2151549-2-andrealmeid@igalia.com
Signed-off-by: André Almeida <andrealmeid@igalia.com>

Author: andrealmeid

drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c

@@ -2447,7 +2447,8 @@ amdgpu_vm_get_vm_from_pasid(struct amdgpu_device *adev, u32 pasid)
  */
 void amdgpu_vm_put_task_info(struct amdgpu_task_info *task_info)
 {
-	kref_put(&task_info->refcount, amdgpu_vm_destroy_task_info);
+	if (task_info)
+		kref_put(&task_info->refcount, amdgpu_vm_destroy_task_info);
 }
 
 /**