Fix missing `return;` statement (this is why we use `-Wunused-value`)

Signed-off-by: Chris Burel <burelc@amazon.com>

Gems/Atom/RHI/DX12/Code/Source/RHI/AliasedHeap.cpp

@@ -113,7 +113,7 @@ namespace AZ
 
             if (!memoryView.IsValid())
             {
-                RHI::ResultCode::OutOfMemory;
+                return RHI::ResultCode::OutOfMemory;
             }
 
             buffer->SetDescriptor(descriptor);