SWDEV-1 - Fix warnings and update disabled test list (#163)

- Fix warnings in some test cases due to unused variables or signed/unsigned comparison.
- Disabled vulkan tests on MI200.

catch/unit/vulkan_interop/hipExternalMemoryGetMappedBuffer.cc

@@ -112,7 +112,9 @@ TEST_CASE("Unit_hipExternalMemoryGetMappedBuffer_Vulkan_Negative_Parameters") {
 
   hipExternalMemoryBufferDesc external_mem_buffer_desc = {};
   external_mem_buffer_desc.size = vk_storage.size;
+#if HT_NVIDIA
   void* hip_dev_ptr = nullptr;
+#endif
 
 // Disabled on AMD due to defect - EXSWHTEC-176
 #if HT_NVIDIA
@@ -150,4 +152,4 @@ TEST_CASE("Unit_hipExternalMemoryGetMappedBuffer_Vulkan_Negative_Parameters") {
         hipErrorInvalidValue);
   }
 #endif
-}
+}