* Rollback protection is useless when device bootloader is UNLOCKED.
  In UNLOCKED state,rollback failures are allowed.

* In UNLOCKED state,even rollback stored_rollback_index[n] on the device won't be updated with flag values.
  But Sadly the timestamp of the SPL still persists on device's devinfo even when you erase that.

* Unlike Pixel Devices,MIUI doesn't set any SPL timestamp to enforce rollback protection.
  So Unfortunately,Because of these reasons users can't relock their device bootloader with stock MIUI.
  So Drop this to save upcoming  users.

Signed-off-by: Dhina17 <dhinalogu@gmail.com>
Change-Id: I35d541a77168d67824beb6dc644de3491b2f9e50