Rename value in top Makefile so it doesn't conflict.
Rename value in top Makefile so it doesn't conflict.

`LIBRARIES` in the top Makefile would conflict with `LIBRARIES` in the
`scripts/make/git.mk`.

Signed-off-by: Tim 'mithro' Ansell <f857bf86f3aed4a1021a5247bd2399c65b7ad5cd@google.com>

google/skywater-pdk