Update git submodules

* Update docs/submodules/so.git from branch 'master'
  to 3d6d255441d913e28639a74c52b057878c6a3b94
  - Merge "Add DeallocateNSSI Sub-process"
  - Add DeallocateNSSI Sub-process
    
    Issue-ID: SO-2368
    
    Signed-off-by: zm330 <zhangminyj@chinamobile.com>
    Change-Id: Ibf443a3d490e48d397f1f3240207b5c00b92695f
    
1 file changed