Remove obsolete llndk_library

Remove llndk_library in favor of cc_library with llndk.symbol_file.

Bug: 170784825
Test: m checkbuild
Test: TestLlndkLibrary
Change-Id: I43580976589a7a2a176d7442be53fa043c0c8324
diff --git a/cc/stub_library.go b/cc/stub_library.go
index 81c8be7..1722c80 100644
--- a/cc/stub_library.go
+++ b/cc/stub_library.go
@@ -31,20 +31,7 @@
 
 // Check if the module defines stub, or itself is stub
 func IsStubTarget(m *Module) bool {
-	if m.IsStubs() || m.HasStubsVariants() {
-		return true
-	}
-
-	// Library which defines LLNDK Stub is also Stub target.
-	// Pure LLNDK Stub target would not contain any packaging
-	// with target file path.
-	if library, ok := m.linker.(*libraryDecorator); ok {
-		if library.Properties.Llndk_stubs != nil {
-			return true
-		}
-	}
-
-	return false
+	return m.IsStubs() || m.HasStubsVariants()
 }
 
 // Get target file name to be installed from this module