Update git submodules

* Update docs/submodules/msb/discovery.git from branch 'master'
  to 2c20a3eb06c4d9b0b83220858245e05e2d83163d
  - update version to 1.2.6
    
    Issue-ID: MSB-463
    Signed-off-by: Huabing Zhao <zhao.huabing@zte.com.cn>
    Change-Id: I031fb14f0e489b3283320ab25c98b9261f6fa8c3
    
1 file changed