Fix build if the config is not updated

• SYSIO4: PB4 or TDI Assignment
0: TDI function selected.
1: PB4 function selected.
• SYSIO5: PB5 or TDO/TRACESWO Assignment
0: TDO/TRACESWO function selected.
1: PB5 function selected.
• SYSIO6: PB6 or TMS/SWDIO Assignment
0: TMS/SWDIO function selected.
1: PB6 function selected.
• SYSIO7: PB7 or TCK/SWCLK Assignment
0: TCK/SWCLK function selected.
1: PB7 function selected.
• SYSIO12: PB12 or ERASE Assignment
0: ERASE function selected.
1: PB12 function selected.

The thing I did not add is warning or compilation failure, (to save the next guy the hassle), at ALL the driver points that uses the these pins.

I did remove this

  /* To use the USART1 as an USART, the SYSIO Pin4 must be bound to PB4
   * instead of TDI
   */

  uint32_t sysioreg = getreg32(SAM_MATRIX_CCFG_SYSIO);
  sysioreg |= MATRIX_CCFG_SYSIO_SYSIO4;
  putreg32(sysioreg, SAM_MATRIX_CCFG_SYSIO);

in sam_lowputc.c in favor of an #error - because the default is an input TDI and driving it blindly to an output TXD1, would be a contention.

CAN support for STM32L4

SAM WDT: Rename up_wdginitialize() functions to something more appropriate for the internal OS interface.

SAM WDT: Rename up_wdginitialize() functions to something more appropriate for the internal OS interface.

enter/leave_critical_section:  In SMP configuration, may attempt to access the task lists before they have been initialized

Fixed Break changes needed CONFIG_SERIAL_TERMIOS to build

Upstream_to_greg

All GCC final arch/*/src/Makefiles: Allow --start-group and --end-group to be redefined for the case where GCC is used to link (instead of LD).  Suggested by Paul Alexander Patience.