Don't use module names with "prebuilt_" prefixes in make dependencies.

The distinction between foo and prebuilt_foo doesn't exist in make, so
this could create invalid dependencies when both source and prebuilt
modules exist and the prebuilts are preferred.

Test: `m` with ART module prebuilts with prefer:true in the tree
Test: m nothing
Bug: 172480615
Change-Id: I90b76a8f38493882b3330d1b6789159852e59d55