Kinetis:  Resolve issue with duplicate definitions of up_putc.  Addition conditional logic to pick just one.

Kinetis:Add LPUART

Approved-by: Gregory Nutt

   Pin out LPUART0 for testing
   Define BOARD_SOPT2_PLLFLLSEL ti select MCGPLLCLK
   Define BOARD_SIM_CLKDIV3_FREQ etal to provide BOARD_LPUART0_FREQ

  HAVE_SERIAL_CONSOLE -> HAVE_UART_CONSOLE to bew consistent with
  HAVE_LPUART_CONSOLE naming

  A board.h file can now specify the:
   1) BOARD_SOPT2_PLLFLLSEL to select the output of the SIM_SOPT2 MUX
     from:
       MCGFLLCLK
       MCGPLLCLK
       USB1PFD
       IRC48MHZ

    2) If it defines BOARD_SIM_CLKDIV3_FREQ then it must define
    BOARD_SIM_CLKDIV3_PLLFLLFRAC and BOARD_SIM_CLKDIV3_PLLFLLDIV
    which wil be used to cpnfigure SIM_CLKDIV3 [PLLFLLFRAC, PLLFLLDIV]

  Add LPUART made UART5 an uption as the K66 does not have UART5

  Add KINETIS_NLPUART setting it to 1 and adjust KINETIS_NUART
  to removed UART5 as the K66 dioes not have UART5

STM32: Remove one residual use of the obsoleted STM32_TIM27_FREQUENCY definition which does not work for all STM32 family members.

Most Ethernet drviers:  Check if the poll timer is running before restarting it at the end of each TX.

sigtimedwait: When timer expires, up_unblock_task() is called.  This is okay in the single CPU case because interrupts are disable in the timer interrupt handler.  But it is insufficient in the SMP case.  enter_ and leave_critical_section() must be called in order to manage spinlocks correctly.

kinetis_enet.c add #define for number of loops for auto negotiation to complete

Approved-by: Gregory Nutt