Fix return in FreeBuffer

[Ryzee119]

Got this

tools/vnproch55x/KT_BinIO.cpp: In member function ‘uint32_t KT_BinIO::FreeBuffer()’:
tools/vnproch55x/KT_BinIO.cpp:53:1: warning: no return statement in function returning non-void [-Wreturn-type]
   53 | }
      | ^