Fixed is_unknown function

Author: oleksandr-pavlyk

libsyclinterface/tests/test_sycl_usm_interface.cpp

@@ -235,8 +235,9 @@ TEST_F(TestDPCTLSyclUSMNullArgs, ChkPointerQueries)
     DPCTLSyclContextRef Null_CRef = nullptr;
     DPCTLSyclUSMRef Null_MRef = nullptr;
     DPCTLSyclUSMType t = DPCTLSyclUSMType::DPCTL_USM_UNKNOWN;
-    auto is_unknown = [=](const char *t) -> bool {
-        return strncmp(t, "unknown", 7) == 0;
+    const char *t = nullptr;
+    auto is_unknown = [=](DPCTLSyclUSMType t_) -> bool {
+        return t_ == DPCTLSyclUSMType::DPCTL_USM_UNKNOWN;
     };
 
     EXPECT_NO_FATAL_FAILURE(t = DPCTLUSM_GetPointerType(Null_MRef, Null_CRef));