Remove vendor symlinks from the root directory

The vendor symlinks are added long time ago to support old devices.
It can be removed now if there are no other newly added use cases.

Bug: 64905218
Bug: 410431879
Test: lunch aosp_arm64-trunk_staging-userdebug && m
Change-Id: I05e30dcd691a9bdb3bdc4f3eacae01e9e1151902