pdl: Remove redundant checks from legacy linter

The checks are now performed by the analyzer module.
The linter scope is still used by the generator so
the module cannot be removed entirely.

Test: cargo test
(cherry picked from https://android-review.googlesource.com/q/commit:6481e40e0b04575bc723b3617a9cf5c92b630208)
Merged-In: Idc3cbe34b86bfd544d539c4926976895a8cc1fb3
Change-Id: Idc3cbe34b86bfd544d539c4926976895a8cc1fb3