Prune non-existing registers from mclk shadow register list. Bug 1799537 Change-Id: I8034a1820ef21e550616a5135856b05c2f375d6f Signed-off-by: Terje Bergstrom <tbergstrom@nvidia.com> Reviewed-on: http://git-master/r/1208018 (cherry picked from commit cb988bb28dd914ea291cedec799d055f3d71d877) Reviewed-on: http://git-master/r/1227266 Reviewed-by: Automatic_Commit_Validation_User GVS: Gerrit_Virtual_Submit