Enable matmul diagonalization on any non-secret matrix (not just constant matrix)

[AlexanderViand-Intel]

heir/lib/Dialect/LinAlg/Conversions/LinalgToTensorExt/LinalgToTensorExt.cpp

Lines 289 to 295 in 1e5cd7e

	// Diagonalize the matrix only if the matrix is a constant.
	auto constantValues =
	dyn_cast<arith::ConstantOp>(publicMatrix.getDefiningOp());
	if (!constantValues) {
	return failure();
	}