Kinetis:Define uart and lpuart versions of [early]serialinit

   Add serial init to centralize UART/LPUART management
   Use kinetis_ not up_ where arch specific
   Defined kinetis_[lp]uart_[early]serialinit to facilitate
    bring up both UARTs and LPUARTs as devices and a console

   Support ordering and merging of serial devices names.