CVE-2024-41008 drm/amdgpu: change vm->task_info handling

In the Linux kernel, the following vulnerability has been resolved:

drm/amdgpu: change vm->task_info handling

This patch changes the handling and lifecycle of vm->task_info object.
The major changes are:

• vm->task_info is a dynamically allocated ptr now, and its uasge is
  reference counted.
• introducing two new helper funcs for task_info lifecycle management
  • amdgpu_vm_get_task_info: reference counts up task_info before
    returning this info
  • amdgpu_vm_put_task_info: reference counts down task_info
• last put to task_info() frees task_info from the vm.

This patch also does logistical changes required for existing usage
of vm->task_info.

V2: Do not block all the prints when task_info not found (Felix)

V3: Fixed review comments from Felix

• Fix wrong indentation
• No debug message for -ENOMEM
• Add NULL check for task_info
• Do not duplicate the debug messages (ti vs no ti)
• Get first reference of task_info in vm_init(), put last
  in vm_fini()

V4: Fixed review comments from Felix

• fix double reference increment in create_task_info
• change amdgpu_vm_get_task_info_pasid
• additional changes in amdgpu_gem.c while porting