basic support of STM32L4VG Discovery board.  Functioning nsh, leds, buttons.  Also compatible with, but not requiring, RNG code in 'arch'.

Remove most unused references to CONFIG_NET_MULTICAST.  Rename other uses of CONFIG_NET_MULTICAST to avoid naming comflicts.

STM32F429I-Disco: Update STM32_RCC_DCKCFGR_PLLSAIDIVR

Nucleo F303RE: Rename ADC pins

Rename the imx/ directories to imx1/ to make room in the namespace for other members of the i.MX family

SAME70: The nomimal frequency of the slow RC oscillator is 32KHz, not 32.768 KHz which has too much false implied accuracy

SAMV71 and SAME70 board:  In sam_appinit.c, need to include sys/types. hf CONFIG_BOARD_INITIAILZE is not defineed.  Noted by Matt Poppe.