Revert "Revert "SF: Remove refresh_rate_switching flag.""

This reverts commit 2a215191.

Reason for revert: Droidcop-triggered revert due to breakage https://android-build.googleplex.com/builds/quarterdeck?branch=git_master&target=hawk-userdebug&lkgb=6180052&lkbb=6180424&fkbb=6180072, bug b/148835312.

Bug: 148835312
Change-Id: Ie8e5d4c683ab7f10051e355a62941bdb37a196b7