add settings to set default freq at boot
more cc1101 config

Move: CONFIG_ADC_NO_START_CONV from drivers/adc/Kconfig to arch/arm/src/stm32[f7]/Kconfig as STM32[F7]_ADC_NO_START_CONV.  Refresh all configurations with any reference to CONFIG_ADC_NO_START_CONV.

STM32F7: warn if no DMA2 configured when using ADC with DMA.  Also correct ADC channel numbers that DMA callback passes to upper half driver.

Move enabling of GPIO peripherals form UART setup to clockconfig.  This is not a UART function.  It is needed by all periphrals.

6loWPAN:  Add some checks for the case where there are multiple network devices and multiple link layer protocols.

not a clean fix, but at least makes DHCP working with CONFIG_NETDEV_MULTINIC

Approved-by: Gregory Nutt <gnutt@nuttx.org>

Revert "Add a placeholder for nucleo-64 boards.  Currently these are in various directories nucleo-f303re, nucleo-f334r8, and nucleo-l476rg but need to be consolidated here because these are all the same boards."

This reverts commit 935cc4e3.