bp2build: do not convert prebuilt cc binaries

These do not have a conversion process yet, do not convert them. Add
more protection against using the wrong conversion for prebuilts in cc.

Test: allowlist project with prebuilt objs/binaries and verify BUILD
      files
Change-Id: Ib26689fa19d6fbb1f5c73ded3b5836165977e987
diff --git a/cc/prebuilt.go b/cc/prebuilt.go
index 4c3c7b4..feae812 100644
--- a/cc/prebuilt.go
+++ b/cc/prebuilt.go
@@ -552,7 +552,7 @@
 }
 
 func NewPrebuiltBinary(hod android.HostOrDeviceSupported) (*Module, *binaryDecorator) {
-	module, binary := NewBinary(hod)
+	module, binary := newBinary(hod, false)
 	module.compiler = nil
 
 	prebuilt := &prebuiltBinaryLinker{