move inlined MxDSObject::SetAtomId to main header

We've confirmed that, despite a function being declared inline, msvc will still make a conventional call in some circumstances. As such, I feel like this is warranted because it's most likely what a developer would have actually written.

LEGO1/mxdsobject.cpp

@@ -34,9 +34,3 @@ void MxDSObject::SetObjectName(const char *p_name)
     }
   }
 }
-
-// OFFSET: LEGO1 0x10005530
-void MxDSObject::SetAtomId(MxAtomId p_atomId)
-{
-  this->m_atomId = p_atomId;
-}