Remove dead CompatibilityMatrix::getSourceMatrixLevel.

Test: TH
Change-Id: Ie4fcc66155a46bcedbda59dfcc6431766e9aef47
diff --git a/CompatibilityMatrix.cpp b/CompatibilityMatrix.cpp
index 0aad75e..eebb2e2 100644
--- a/CompatibilityMatrix.cpp
+++ b/CompatibilityMatrix.cpp
@@ -471,15 +471,6 @@
     return type() == SchemaType::DEVICE ? device.mVendorNdk.version() : "";
 }
 
-Level CompatibilityMatrix::getSourceMatrixLevel(const MatrixKernel* matrixKernel) const {
-    CHECK(std::find_if(framework.mKernels.begin(), framework.mKernels.end(),
-                       [matrixKernel](const auto& e) { return &e == matrixKernel; }) !=
-          framework.mKernels.end());
-    Level ret = matrixKernel->getSourceMatrixLevel();
-    if (ret != Level::UNSPECIFIED) return ret;
-    return level();
-}
-
 KernelVersion CompatibilityMatrix::getLatestKernelMinLts() const {
     if (type() != SchemaType::FRAMEWORK) {
         return {};
diff --git a/include/vintf/CompatibilityMatrix.h b/include/vintf/CompatibilityMatrix.h
index a5aaa62..ee72d18 100644
--- a/include/vintf/CompatibilityMatrix.h
+++ b/include/vintf/CompatibilityMatrix.h
@@ -148,10 +148,6 @@
     bool matchInstance(HalFormat format, const std::string& halName, const Version& version,
                        const std::string& interfaceName, const std::string& instance) const;
 
-    // Return the level of the matrixKernel object that it is originally from.
-    // Prerequisite: matrixKernel is in mKernels.
-    Level getSourceMatrixLevel(const MatrixKernel* matrixKernel) const;
-
     // Return the minlts of the latest <kernel>, or empty value if any error (e.g. this is not an
     // FCM, or there are no <kernel> tags).
     [[nodiscard]] KernelVersion getLatestKernelMinLts() const;