vndk-sp: Fix vndk-sp-unused computation

This commit removes vndk-sp-indirect libs from vndk-sp-unused.  They
are actually being used (although indirectly).

Bug: 37867089
Test: libhwbinder.so is removed from vndk-sp-unused given sailfish images.
Change-Id: I7a3b253408c53f1d81d1fea39f79e3fe09f6fb75