Update git submodules

* Update prebuilts/clang/host/linux-x86 from branch 'master'
  to 9d8adb45518e89a0cafeb1b9d562517965939121
  - prebuilts: clang: update readme
    
    Refresh the info in the readme, since some parts of the platform have
    moved forward, and now that we have clang-r353983d.
    
    Bug: 131714073
    Change-Id: I542935b1b3832934dac034bc8a89029c85f9943b
    
1 file changed