PB timeout has been removed in gm20b, so write it only in gk20a. Change-Id: I2aab92fe7d1d5de151dad768f8b3f6901ec0bbb0 Signed-off-by: Terje Bergstrom <tbergstrom@nvidia.com> Reviewed-on: http://git-master/r/486358 Reviewed-by: Automatic_Commit_Validation_User Reviewed-by: Seshendra Gadagottu <sgadagottu@nvidia.com> Tested-by: Seshendra Gadagottu <sgadagottu@nvidia.com> Reviewed-by: Deepak Nibade <dnibade@nvidia.com> Reviewed-by: Kevin Huang (Eng-SW) <kevinh@nvidia.com>