Revert "ANDROID: Allow MODVERSIONS + Rust with no symbol export"

This reverts commit 9d239c32.

This should no longer be needed as [1] and [2] are now being merged into
android-mainline tree. Plus this causes merge conflicts with [2] itself
when pulling 'kbuild-v6.14' upstream tag.

Cc: Matthew Maurer <mmaurer@google.com>
Link: https://lore.kernel.org/all/20240925233854.90072-1-mmaurer@google.com/ [1]
Link: https://lore.kernel.org/all/20241008183823.36676-21-samitolvanen@google.com/

 [2]
Change-Id: I841cf934179d0c25dc62bd3514347051a71e4d0c
Signed-off-by: Carlos Llamas <cmllamas@google.com>